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LED switching power supply PCB board design

星期五, 28 3 月, 2025

LED switching power supply PCB board design,In the design of switching power supplies, if the PCB board is not designed properly, it will radiate too much electromagnetic interference. The following seven tricks are summarized for the design of PCB boards that ensure stable power supply operation: by analyzing the matters that need to be paid attention to in each step, you can easily design the PCB board step by step!

Step 1

Design process from schematic to PCB: Establish component parameters – > Input schematic netlist – > Design parameter setting – > Manual layout – > Manual wiring – > Verify design – > Review – > CAM output.

LED switching power supply PCB board design

Step 2

Parameter setting: The spacing between adjacent wires must meet the electrical safety requirements, and the spacing should be as wide as possible for easy operation and production. The spacing should at least be suitable for the voltage to be tolerated. When the wiring density is low, the spacing between signal lines can be appropriately increased. The signal lines with high and low levels should be as short as possible and the spacing should be increased. In general, the wiring spacing is set to 8mil. The distance from the edge of the inner hole of the pad to the edge of the printed circuit board should be greater than 1mm to avoid pad defects during processing. When the trace connected to the pad is thin, the connection between the pad and the trace should be designed into a water drop shape. The advantage of this is that the pad is not easy to peel, but the trace and the pad are not easy to disconnect.

Step 3

Component layout practice has proved that even if the circuit schematic is designed correctly, improper printed circuit board design will have an adverse effect on the reliability of electronic equipment. For example, if two thin parallel lines on a printed circuit board are very close to each other, a delay in the signal waveform will be formed, and reflected noise will be formed at the end of the transmission line; interference caused by inconsiderate consideration of the power supply and ground line will reduce the performance of the product. Therefore, when designing a printed circuit board, you should pay attention to using the correct method. Each switching power supply has four current loops:
(1) Power switch AC loop
(2) Output rectifier AC loop
(3) Input signal source current loop
(4) Output load current loop
The input loop charges the input capacitor through a current that is close to DC, and the filter capacitor mainly plays a broadband energy storage role; similarly, the output filter capacitor is also used to store high-frequency energy from the output rectifier and eliminate the DC energy of the output load loop. Therefore, the terminals of the input and output filter capacitors are very important. The input and output current loops should be connected to the power supply only from the terminals of the filter capacitors; if the connection between the input/output loop and the power switch/rectifier loop cannot be directly connected to the terminals of the capacitor, the AC energy will be radiated from the input or output filter capacitor to the environment. The AC circuit of the power switch and the AC circuit of the rectifier contain high-amplitude trapezoidal currents. The harmonic components in these currents are very high, and their frequencies are much higher than the switching base frequency. The peak amplitude can be as high as 5 times the continuous input/output DC current amplitude, and the transition time is usually about 50ns. These two circuits are prone to electromagnetic interference, so these AC circuits must be laid out before other printed wiring in the power supply. The three main components of each circuit, filter capacitors, power switches or rectifiers, and inductors or transformers, should be placed adjacent to each other, and the positions of the components should be adjusted to make the current path between them as short as possible.
The method of establishing the layout of the switching power supply is similar to its electrical design. The design process is as follows:
Place the transformer Design the power switch current loop Design the output rectifier current loop Control circuit connected to the AC power circuit Design the input current source loop and input filter Design the output load loop and output filter According to the functional units of the circuit, when laying out all the components of the circuit, the following principles must be met:
(1) First, consider the size of the PCB. When the PCB size is too large, the printed lines are long, the impedance increases, the anti-noise ability decreases, and the cost increases; if it is too small, the heat dissipation is poor, and the adjacent lines are susceptible to interference. The shape of the circuit board is rectangular, with an aspect ratio of 3:2 or 4:3. The components located at the edge of the circuit board are generally not less than 2mm away from the edge of the circuit board.
(2) When placing components, consider the subsequent welding and do not place them too densely;
(3) The components of each functional circuit are centered and the layout is carried out around it. The components should be arranged evenly, neatly and compactly on the PCB. The leads and connections between the components should be minimized and shortened as much as possible, and the decoupling capacitor should be as close to the VCC of the device as possible.
(4) For circuits working at high frequencies, the distribution parameters between components should be considered. Generally, the components of the circuit should be arranged in parallel as much as possible. This is not only beautiful, but also easy to assemble and solder, and easy to mass produce.
(5) Arrange the positions of each functional circuit unit according to the circuit process, so that the layout is convenient for signal flow and the signal keeps the same direction as much as possible.
(6) The first principle of layout is to ensure the wiring pass rate. When moving components, pay attention to the connection of flying wires and put the components with connection relationships together.
(7) Reduce the loop area as much as possible to suppress the radiation interference of the switching power supply.

Step 4

Wiring The switching power supply contains high-frequency signals. Any trace on the PCB can act as an antenna. The length and width of the trace will affect its impedance and inductance, thereby affecting the frequency response. Even traces that pass DC signals can couple to RF signals from adjacent traces and cause circuit problems (even radiate interference signals again). Therefore, all traces that pass AC current should be designed to be as short and wide as possible, which means that all components connected to the traces and to other power lines must be placed very close. The length of the trace is proportional to the inductance and impedance it exhibits, while the width is inversely proportional to the inductance and impedance of the trace. The length reflects the wavelength of the trace response. The longer the length, the lower the frequency of the electromagnetic wave that the trace can send and receive, and it can radiate more RF energy. According to the size of the printed circuit board current, try to increase the width of the power line and reduce the loop resistance. At the same time, make the direction of the power line and ground line consistent with the direction of the current, which helps to enhance the anti-noise ability. Grounding is the bottom branch of the four current loops of the switching power supply. It plays an important role as a common reference point of the circuit. It is an important method to control interference. Therefore, the placement of the grounding wire should be carefully considered in the layout. Mixing various groundings will cause unstable power supply operation.
The following points should be noted in the grounding design:

Correctly select single-point grounding. Usually, the common end of the filter capacitor should be the connection point where other grounding points are coupled to the AC ground of large current. The grounding points of the same circuit should be as close as possible, and the power filter capacitor of the circuit at this level should also be connected to the grounding point of this level. The main consideration is that the current flowing back to the ground from each part of the circuit is changing. The impedance of the actual flowing line will cause the ground potential of each part of the circuit to change and introduce interference. In this switching power supply, the inductance between its wiring and devices has little effect, while the loop current formed by the grounding circuit has a greater impact on interference. Therefore, a single-point grounding is used, that is, the ground wires of several devices in the power switch current loop are connected to the ground pin, and the ground wires of several devices in the output rectifier current loop are also connected to the ground pin of the corresponding filter capacitor. In this way, the power supply works more stably and is not easy to self-excite. When a single point cannot be achieved, two diodes or a small resistor are connected to the common ground. In fact, it can be connected to a relatively concentrated piece of copper foil.
Try to thicken the ground wire. If the ground wire is very thin, the ground potential changes with the change of current, causing the timing signal level of the electronic equipment to be unstable and the anti-noise performance to deteriorate. Therefore, it is necessary to ensure that each large current ground end uses a printed line as short and wide as possible, and try to widen the width of the power and ground wires. The ground wire is wider than the power line. Their relationship is: ground wire>power line>signal line. If possible, the width of the ground wire should be greater than 3mm, or a large copper layer can be used as a ground wire. On the printed circuit board, all unused areas are connected to the ground as ground wires. When performing global wiring, the following principles must be followed:
(1) Wiring direction: From the welding surface, the arrangement of components should be kept consistent with the schematic diagram as much as possible, and the wiring direction should be consistent with the wiring direction of the circuit diagram. Because various parameters usually need to be tested on the welding surface during the production process, this is convenient for inspection, debugging and maintenance during production (Note: It refers to the premise of meeting the circuit performance and the requirements of the whole machine installation and panel layout).
(2) When designing the wiring diagram, the wiring should have as few turns as possible, the line width on the printed arc should not change suddenly, the wire corner should be ≥90 degrees, and the lines should be simple and clear.
(3) No cross circuits are allowed in the printed circuit. For lines that may cross, “drilling” and “winding” can be used to solve them. That is, let a lead “drill” from the gap under the feet of other resistors, capacitors, and transistors In the past, or from one end of a lead that may cross, in special cases, if the circuit is very complicated, in order to simplify the design, it is also allowed to use wire jumper to solve the problem of cross circuit. Because a single-sided board is used, the through-hole components are located on the top surface and the surface-mount components are located on the bottom surface, so when laying out, the through-hole components can overlap with the surface-mount components, but the pads must be avoided from overlapping.
Input ground and output ground This switching power supply is a low-voltage DC-DC. To feed the output voltage back to the primary of the transformer, the circuits on both sides should have a common reference ground, so after the ground wires on both sides are coppered separately, they must be connected together to form a common ground.

Step 5

Inspection: After the wiring design is completed, it is necessary to carefully check whether the wiring design conforms to the rules set by the designer. At the same time, it is also necessary to confirm whether the rules set meet the requirements of the printed circuit board production process. Generally, check whether the distance between lines, lines and component pads, lines and through holes, component pads and through holes, and through holes are reasonable and meet production requirements. Whether the width of the power line and the ground line is appropriate, and whether there is any place in the PCB that can widen the ground line. Note: Some errors can be ignored. For example, part of the outline of some connectors is placed outside the board frame, which will cause errors when checking the spacing; in addition, after each modification of the routing and vias, copper must be re-coated.

Step 6

Review According to the “PCB Checklist”, the content includes design rules, layer definition, line width, spacing, pads, and via settings. It is also necessary to focus on reviewing the rationality of the device layout, the routing of the power and ground network, the routing and shielding of the high-speed clock network, and the placement and connection of the decoupling capacitors.

Step 7

a. The layers that need to be output are the wiring layer (bottom layer), the silk screen layer (including the top silk screen and the bottom silk screen), the solder mask layer (bottom solder mask), the drilling layer (bottom layer), and the drilling file (NCDrill)
b. When setting the layer of the silk screen layer, do not select PartType, select the Outline, Text, and Line of the top (bottom) and silk screen layers
c. When setting the layer of each layer, select Board Outline, and when setting the layer of the silk screen layer, do not select PartType, select the Outline, Text, and Line of the top (bottom) and silk screen layers.
d. When generating the drilling file, use the default settings of PowerPCB and do not make any changes.

What is Mouse Bite in PCB?

What is mouse bites PCB? In the PCB world, a mouse bite refers to a small hole or notch created at the edges of the PCB panel. These notches are used to facilitate the separation of individual boards from the panel. The term “mouse bite” comes from the small, round shape of the indentation, resembling a tiny “bite” taken out of the PCB. The notches are typically placed along the edges of the PCB during the manufacturing process and are especially useful in high-volume production, where multiple PCBs are often manufactured as part of a larger panel.

Purpose of PCB Mouse Bites

The primary purpose of mouse bites in PCB design is to assist in the breakaway process. During the manufacturing of PCBs, multiple boards are often produced in a single panel. After fabrication, these panels must be separated into individual PCBs. Without a proper method, separating them could result in damage to the boards or pose a risk to delicate components.

Mouse bites are engineered to provide a controlled, predictable break. When the panel is ready for separation, the notches help to guide the break and reduce the chance of fractures or warping. Additionally, mouse bites are essential in panels where the PCBs are tightly packed, ensuring the separation process remains smooth and efficient.

What is Mouse Bites PCB? Mouse Bites vs. V-Groove

Advantages of Mouse Bite in PCB

There are several notable advantages to using mouse bites in PCB design:

Controlled Separation: Mouse bites provide a controlled break, minimizing the risk of damaging the PCB during the separation process. They guide the break and ensure that it occurs where it’s most needed.
Improved Efficiency: Adding mouse bites to a PCB panel significantly speeds up the manufacturing process. This allows for quicker breakaway times, resulting in more efficient production cycles.
Cost-Effective: By reducing the likelihood of breakage or errors, mouse bites save money on rework, damaged boards, or production delays.
Design Flexibility: Mouse bites are particularly beneficial when manufacturing smaller PCBs within a larger panel. They offer design flexibility without compromising the integrity of the individual boards.

How Do You Add Mouse Bites to PCB?

Adding mouse bites to a PCB design is typically done in the design phase. The process involves creating small circular notches along the edges of the PCB. These notches are strategically placed where separation is intended.

To add mouse bites in PCB design software, follow these steps. Here’s a step-by-step guide on how to place mouse bites in Altium Designer:

1. Open Your PCB Project

Start Altium Designer and open the PCB project that you’re working on.

2. Create or Edit the PCB Panel

If you’re working with a multi-board panel, go to Design > Define Board Shape to create or edit the panel where you want to add the mouse bites.

3. Set Up the Mouse Bite Tool

In Altium Designer, go to the Tools menu and select Create Polygon Pour. This tool can be used to make the necessary notches (mouse bites) along the edges of the PCB.

4. Select the Edge of the PCB

With the polygon pour tool activated, click along the edge of the PCB where you want the mouse bites to appear.

5. Define the Hole Parameters

Define the size and shape of the mouse bite by adjusting the hole diameter and spacing. Mouse bites are typically circular, and you can customize the hole size to fit your design requirements (e.g., 0.3mm to 1.2mm).

6. Place the Mouse Bites

Position the mouse bites along the edges of the panel. Make sure the notches are evenly spaced and aligned according to your design rules.

7. Ensure Proper Clearance

Verify that there is enough clearance from the PCB edges (at least 0.3mm) to avoid damage or cracking during separation.

8. Check the Design Rules

Review your Design Rules to ensure the mouse bites meet the necessary standards for the board’s separation and manufacturing process.

9. Save the Design

Once you’re satisfied with the placement and spacing, save your design.

10. Export the Files

After placing the mouse bites, export your Gerber files for manufacturing by going to File > Fabrication Outputs and selecting the appropriate output format.

By following these steps, you can efficiently place mouse bites in your PCB design using Altium Designer. If you are not familiar with Altium software, you are welcome to contact Best Technology team, we offer free technical support for our customers.

What Is the Difference Between V-Groove and Mouse Bites?

Both V-groove and mouse bites are methods used to separate PCBs after fabrication, but there are some key differences between the two:

V-Groove

V-grooves are deeper cuts, often formed by a mechanical process that creates a “V” shape along the edge of the PCB. This type of break is typically used for larger panels and requires additional precision during manufacturing.

Pros: High precision, smooth cutting surface, suitable for automated production, and aesthetically pleasing. It is ideal for applications with strict precision requirements.
Cons: The edge strength is relatively low, making it unsuitable for applications that need to endure high mechanical stress. For PCBs with more than a certain number of layers, controlling the V-groove depth becomes more challenging, potentially affecting product quality.

Mouse Bites

Mouse bites are used as a method for inter-layer connections within multi-layer PCBs, especially in high-density interconnect (HDI) designs. Small, deep holes are drilled between the layers of the PCB, and copper is plated on the hole walls to create electrical connections between layers.

Pros: High space utilization, especially suitable for compact designs. It improves signal transmission performance by reducing signal delay and cross-talk. It is suitable for more complex multi-layer board designs.
Cons: The manufacturing process is complex and costly. It requires high precision in design and testing, increasing development difficulty.

Tips for Selecting the Right PCB Breakaway Method

Choosing the correct breakaway method is crucial for ensuring your PCBs are separated cleanly and efficiently. Here are some tips to consider:

Panel Size: Larger panels may benefit from V-grooves, while smaller or more delicate boards are better suited for mouse bites.
Design Considerations: If your design has sensitive components near the edge, mouse bites may be a better option since they cause less stress to the board during separation.
Cost and Efficiency: Mouse bites are typically more cost-effective for smaller runs, while V-grooves may be better for high-volume production.

Design Guide for Mouse Bites PCB

The design rules for mouse bites are critical for ensuring the reliability and stability of the PCB. Below are the requirements for the design rules of stamped holes in PCBs:

1. Hole Diameter: The diameter of the mouse bites should be selected based on the design requirements and the connected components. Typically, common hole sizes range from 0.3mm to 1.2mm.

2. Edge Clearance: To ensure that the hole has enough distance from the PCB edge and avoid cracking or peeling, the design rules require a minimum clearance of 0.3mm from the edge.

3. Hole Layout: The layout of the holes in PCB design is crucial. Holes should be distributed more concentrically and evenly across the PCB to avoid overcrowding, ensuring the stability and reliability of connections.

4. Hole Reinforcement: Certain components, such as resistors and capacitors, may loosen due to mechanical shock or vibration. To increase stability, design rules require the presence of pads or filling rings around the mouse bites hole to enhance the connection’s sturdiness.

5. Pad Size: To ensure welding quality and reliability, the mouse bites should be paired with a sufficiently large pad. The pad’s diameter is generally at least twice the hole size, ensuring ample space during the soldering process.

6. Trace Routing: To maintain the electrical performance and stability of the mouse bites, traces should avoid passing directly through the hole whenever possible. If traces must pass through the hole, they should not intersect with pins, and dead zones should be avoided.

7. Trace Spacing: To prevent interference between traces and avoid soldering errors, the design rules require sufficient trace spacing between stamped holes.

FAQs

Q1: Can I use mouse bites in all PCB designs?

Yes, mouse bites are ideal for most PCB designs that need to be separated after manufacturing. However, they are best suited for smaller boards or those with less sensitive components along the edges.

Q2: How do I avoid damaging my PCB during the separation process?

By using mouse bites or V-grooves, you can reduce the risk of damaging your PCB. Properly designed notches ensure a controlled break, which minimizes the risk of cracks or fractures.

Q3: Are mouse bites more cost-effective than V-grooves?

Yes, mouse bites are generally more affordable than V-grooves, especially for smaller production runs.

Q4: Can mouse bites be placed on the entire PCB edge?

Yes, mouse bites can be placed along the entire edge of the PCB, but it’s important to leave enough margin from the board’s edge to prevent cracks or damage.

Q5: How do mouse bites differ from traditional breakaway tabs?

Mouse bites create small perforations that guide the break along the PCB’s edge, while traditional breakaway tabs usually involve larger cuts or slots. Mouse bites provide more precise separation with less risk of board damage.

What is a Silkscreen on a PCB?

Silkscreen is a layer of ink applied to the PCB’s surface. Typically, you’ll find it on the top side, although it can also be placed on the bottom. Screen silkscreen is usually used to indicate useful information on the PCB board, which can help the user in the assembly process, and is used to mark the component value, part number, polarity and other information, but also contains the version, manufacturer and other information. You’ll often see labels, symbols, and small icons that guide people assembling or repairing the board. In a busy PCB layout, the silkscreen is a roadmap for where everything goes, helping avoid mix-ups and reducing assembly time.

What is the Purpose of Silkscreen?

The silkscreen layer’s primary purpose is to add clarity. By showing clear labels for components, it reduces the chance of error during assembly. When it’s time to troubleshoot, silkscreen also makes life easier by letting technicians locate parts quickly. Silkscreen may include warnings, brand logos, or model names, all helping to make the board more informative. Essentially, it saves time, improves accuracy, and simplifies the process from start to finish.

Silkscreen Information Include on PCB

Silkscreen can be letters, numbers, text. PCB screen printing is done during the PCB manufacturing process, but is used for the PCB assembly process step. Here are some common information that can be silkscreened.

1. Polarity reference sign

2. Determine the test point

3. Component bit number reference mark

4. Component boundary

5, component pin mark

6. Unique identification number for each board

7. Company logo

8. Version number

9. Date code

10, Manufacturer’s logo, serial number, lot number

11. Warning symbols

12. Regulatory marks

Regulatory marks are used to indicate that a design has passed inspection or complies with specific regulations. RoHS, FCC, CE and e-waste disposal marks are commonly found on consumer and commercial products that have passed relevant inspections.

If another mark is seen on a design that has been inspected for safety: the UL mark, this mark indicates that the design was manufactured and assembled by a UL-certified manufacturer according to the UL796 and UL94 standards.

What are the Colors of PCB Silkscreen?

The color of silkscreen is chosen based on readability. White is the most common choice, especially on boards with a green soldermask, because it has a very good readability. And it is a public color and is more friendly to manufacture.

In addition, other colors such as yellow, red, black are also commonly used in the initial stage of PCB board design, pink screen printing is a favorite color of some PCB Layout, but it is usually not recommended to use this color, because it has special characteristics and is not friendly to the manufacturing process.

PCB Silkscreen Symbol

Silkscreen symbols represent various components on the board, making it easier to find specific parts and identify their functions. For instance, “R” stands for resistors, “C” for capacitors, and “U” for integrated circuits. Symbols also show component orientation and polarity, which is crucial for accuracy in assembly. Well-organized symbols on the silkscreen save time and effort, especially during maintenance, as they allow technicians to pinpoint components instantly.

What is the Difference Between Silkscreen and Solder Mask?

Solder mask is a green or other color layer coated on the circuit board, which can play a role in protecting the board. Because there are usually many wires and components on the surface of the circuit board, it is easy to have problems such as short circuit or virtual welding during the welding process, which will lead to damage to the circuit board. Solder resistance layer can effectively avoid the occurrence of this problem. At the same time, the solder resistance layer can also improve the corrosion resistance and mechanical strength of the circuit board.

Solder mask and silkscreen are both coated on the circuit board, but their roles are different. The solder resistance layer is mainly used to protect the circuit board from welding problems, and the screen printing is used to identify the components and related information on the circuit board. In addition, the solder mask is usually green or other bright colors, and the screen printing is usually white or other light colors for easy identification.

What is the Screen Printing Method of PCB?

There are totally three ways to print silkscreen on a PCB surface, manual screen printing, LPI, and DLP. Let me introduce them for you:

1. Manual screen printing

Do this on the PCB when the registration tolerance is 0.005 inches or the line width is greater than 0.007 inches. Perform manual screen printing using a mold containing text and traces. Traces are made of nylon. The ink is directed to the layer or laminate by stenciling. Next, the ink is cured in a baking oven. This is one of the easy ways to create a silk-screen layer, and it also supports large fonts. Perfecting the art can take years.

2. Liquid Photo Imaging (LPI):

This method is used to screen print threads larger than 4 million. The process of LPI is almost the same as the application of solder mask. In this method, however, the laminate is coated with epoxy resin and then placed under ultraviolet light. The plate is cured and then developed. This method ensures greater accuracy than manual screen printing.

LPI uses white, which requires more ink than the other two types of screen printing. Such prints take a long time to set up.

3. Direct Legend Printing (DLP):

This is one of the other three processes that is expensive. In this process, an inkjet projector and acrylic ink will be used. The ink is applied to the PCB using CAD software. The ink is then exposed to ultraviolet light. Acrylic links are not suitable for PCBS that may have a silver surface.

How Thick is the Silkscreen on a PCB?

Silkscreen thickness is usually about 0.02 mm. This thin layer is enough to make the markings visible without interfering with the board’s layout or operation. The thinness is key because it keeps the board easy to handle without any obstruction or interference, but it’s thick enough that it won’t wear off easily during normal use.

Best Technology highly specialized not only in quick-turn PCB prototype and PCB assembly, but also medium and small volume PCB fabrication. We can provide silkscreen on your PCBs for you with various colors, and we will try our best to meet the demands of silkscreen. If you have any questions, please feel free to contact us, we will be happy to help you.

Is the circuit board DC or AC?

Circuit boards can transmit both direct current and alternating current. In modern electronic products, we use alternating current for power supply, so most circuit boards are also designed to transmit alternating current. Of course, in some special application scenarios, some circuit boards also need to transmit direct current. Whether transmitting direct current or alternating current, the circuit board needs to meet the requirements of the transmitted current.

What is the PCB in AC?

The alternating current in PCB refers to the current whose direction changes periodically, that is, alternating current (AC). The application of alternating current in PCB is mainly reflected in power conversion and power transmission. PCB power supply usually converts AC into stable direct current (DC) output to meet the demand of electronic equipment for stable power supply. PCB power supply converts AC into the required DC through components such as transformers, rectifiers, filters and voltage regulators, and provides stable power output.

How to calculate the bandwidth of AC in PCB traces

The calculation of AC PCB trace width can be performed by the following formula: W = (I / J) * K, where W represents the trace width, I represents the current, J represents the current density, and K represents a coefficient related to materials and processes. ‌This formula shows that the trace width is related to the current, current density, and material properties‌.

AC in PCB Design Guide

Current Carrying Capacity: The width of a trace directly affects its ability to handle current without exceeding temperature limits or causing excessive voltage drop.
‌Impedance Control: In high-frequency applications, maintaining controlled impedance is critical for signal integrity. Trace width, trace spacing, and dielectric properties affect the characteristic impedance of the transmission line.
‌Heat Dissipation: Adequate trace width helps to effectively dissipate heat, preventing thermal issues such as trace delamination or solder joint failure.
‌Voltage Drop: Narrower traces exhibit higher resistance, resulting in increased voltage drop along the length of the trace. By adjusting the trace width, the voltage drop can be minimized.
‌Manufacturability: The PCB manufacturing process imposes restrictions on the minimum trace width, and designers must balance performance requirements with manufacturability constraints. ‌2.
‌Minimum Trace Width: Most manufacturers have a minimum trace width of 6mil or 0.152mm, and typically use traces of 0.254-0.3mm.
‌Material and Process Deviations: Due to the possibility of material and process deviations in the actual PCB manufacturing process, a certain margin needs to be left when calculating the line width.
‌Signal Integrity Simulation‌: Perform signal integrity simulations to ensure impedance is controlled and signal degradation due to reflections, crosstalk, or transmission line effects is minimized‌

AC in PCB wiring

The current trend is that the power supply voltage is getting lower and lower (especially for highly integrated digital devices), the space occupied is getting smaller and smaller, the weight is getting lighter and lighter, and the efficiency is getting higher and higher, which requires the precise design of the power supply circuit starting from the PCB.

Safety distance includes electrical clearance (spatial distance), creepage distance (surface distance) and insulation penetration distance…

Electrical clearance: the shortest distance between two adjacent conductors or one conductor and the adjacent motor housing surface measured along the air.
Creepage distance: the shortest distance between two adjacent conductors or one conductor and the adjacent motor housing surface measured along the insulation surface.

Determination of electrical clearance:

The distance can be determined according to the measured working voltage and insulation level

The electrical clearance size requirements of the primary side line are shown in Table 3 and Table 4

The electrical clearance size requirements of the secondary side line are shown in Table 5

But usually: Primary side AC part: L-N ≥ 2.5mm before the fuse, L.N PE (earth) ≥ 2.5mm, no requirements are made after the fuse is installed, but a certain distance should be maintained as much as possible to avoid short circuit damage to the power supply.

Primary side AC to DC part ≥2.0mm

Primary side DC ground to earth ≥2.5mm (primary side floating ground to earth)

Primary side to secondary side ≥4.0mm, components connected between primary and secondary sides

Secondary side gap ≥0.5mm

Secondary side ground to earth ≥1.0mm

Note: Before determining whether it meets the requirements, the internal parts should be applied with a force of 10N and the outer shell with a force of 30N to reduce the distance so that the space distance still meets the requirements under the worst case.

Determination of creepage distance:

Based on the working voltage and insulation level, the creepage distance can be determined by looking up Table 6

But usually: (1), primary side AC part: L-N ≥2.5mm before the fuse, L.N earth ≥2.5mm, no requirement is required after the fuse, but try to keep a certain distance to avoid short circuit damage to the power supply.

(2) Primary side AC to DC part ≥2.0mm

(3) Primary side DC ground to ground ≥4.0mm such as primary side ground to earth

(4) Primary side to secondary side ≥6.4mm, such as optocoupler, Y capacitor and other components, the foot spacing ≤6.4mm needs to be slotted.

(5) Secondary side parts ≥0.5mm

(6) Secondary side ground to earth ≥2.0mm or more

(7) Transformer two-stage ≥8.0mm or more

Insulation penetration distance:

It should meet the following requirements according to the working voltage and insulation application:

For working voltage not exceeding 50V (71V AC peak or DC value), there is no thickness requirement;
The minimum thickness of additional insulation should be 0.4mm;
When the reinforced insulation is not subjected to any mechanical stress that may cause deformation or performance degradation of the insulating material at normal temperature, the minimum thickness of the reinforced insulation should be 0.4mm. If the insulation provided is used in the protective casing of the equipment and will not be bumped or scratched during maintenance by the operator, and any of the following conditions apply, the above requirements do not apply to thin insulating materials regardless of their thickness;
For additional insulation, at least two layers of material are used, each of which can pass the dielectric strength test for additional insulation; or:
For additional insulation composed of three layers of material, any combination of two layers of material can pass the dielectric strength test for additional insulation; or:
For reinforced insulation, at least two layers of material are used, each of which can pass the dielectric strength test for reinforced insulation; or:
For reinforced insulation composed of three layers of insulating material, any combination of two layers of material can pass the dielectric strength test for reinforced insulation.

Points to note about wiring process:

Flat components such as capacitors must be flat without glue.

If the distance between two conductors can be shortened by applying a force of 10N, which is less than the safety distance requirement, glue can be used to fix the part to ensure its electrical clearance.

When laying PVC film inside some shell equipment, attention should be paid to ensuring the safety distance (pay attention to the processing technology).

When fixing the parts with glue, be careful not to leave foreign matter such as glue wire on the PCB board.

When processing parts, insulation damage should not be caused.

Requirements for flame-proof materials:

Heat shrink tubing V-1 or VTM-2 or above; PVC tubing V-1 or VTM-2 or above

Teflon tubing V-1 or VTM-2 or above; plastic materials such as silicone sheets, insulating tape V-1 or VTM-2 or above

PCB board 94V-1 or above

Regarding insulation level

(1) Working insulation: insulation required for normal operation of equipment

(2) Basic insulation: insulation that provides basic protection against electric shock

(3) Supplementary insulation: independent insulation applied in addition to basic insulation to protect against electric shock in case of basic insulation failure

(4) Double insulation: insulation consisting of basic insulation plus supplementary insulation

(5) Reinforced insulation: a single insulation structure that provides the same level of protection against electric shock as double insulation under the conditions specified in this standard

The applicable situations of various insulation are as follows:

A. Operational insulation

a. Between parts with different voltages

b. Between ELV circuits (or SELV circuits) and grounded conductive parts.

B. Basic insulation

a. Between parts with dangerous voltages and grounded conductive parts;

b. Between SELV circuits with dangerous voltages and grounding-dependent;

c. Between the primary power conductor and the grounded shield or the core of the main power transformer;

d. As part of double insulation.

C. Supplementary insulation.

a. Generally speaking, between accessible conductive parts and parts that may carry dangerous voltages after basic insulation is damaged, such as:

Ⅰ. Between the surface of handles, knobs, handles or similar objects and their ungrounded axis.

Ⅱ. Between the metal casing of the second category equipment and the outer skin of the power cord passing through this casing.

Ⅲ. Between the ELV circuit and the ungrounded metal casing.

b. As part of double insulation

D. Double insulation

Double insulation Reinforced insulation

Generally speaking, between the primary circuit and

a. between accessible ungrounded conductive parts, or

b. between floating SELV circuits, or

c. between TNV circuits

Double insulation = basic insulation + supplementary insulation

Note: ELV circuit: extra low voltage circuit

Under normal working conditions, the AC peak value between conductors or between any conductors does not exceed 42.4V or the DC value does not exceed 60V.

SELV circuit: safety extra low voltage circuit.

A properly designed and protected secondary circuit so that under normal conditions or single fault conditions, the voltage between any two accessible parts, and between any accessible parts and the protective grounding terminal of the equipment (only for Class I equipment) will not exceed the safety value.

TNV: communication network voltage circuit

Under normal working conditions, the circuit carrying communication signals

Difference between direct current and alternating current

‌The main differences between DC and AC include direction and polarity, voltage change, current loss, transformer use, and application scenarios.

‌Direction and polarity:

DC: The direction of the current remains unchanged, and the electrons flow from the positive electrode to the negative electrode.

AC: The direction of the current changes periodically, and the electrons flow back and forth between the positive and negative electrodes. ‌
‌Voltage change:

DC: The voltage remains constant and does not change over time.

AC: The voltage magnitude and direction change periodically over time. For example, the mains is an AC with a sine waveform.

‌Current loss:

DC: Fault losses are relatively small.

AC: There is capacitive current, and there is capacitive current in the transmission line. ‌
‌Transformer use:

DC: The voltage cannot be changed using a transformer.

AC: The voltage can be changed using a transformer, which is suitable for boosting voltage to reduce losses during long-distance transportation.

‌Application scenarios:

DC: Suitable for low-voltage electrical appliances and occasions that require stable current.
‌Alternating current‌: Suitable for household and industrial use, using transformers to change voltage to suit different needs.‌

FAQ About AC in PCB

FAQ About AC in PCB

Q: The relationship between PCB current and line width. Is the current divided into AC or DC?
A: The relationship between PCB current and line width is not divided into AC or DC. In terms of the nature of the lines on the PCB, the lines are all made of copper materials, and both AC and DC can pass. However, how much current can pass depends on the cross-sectional area of the line on your PCB. That is, line width x thickness of the copper foil of the line. If the cross-sectional area of the line is small, only small current signals can pass, and if the cross-sectional area is large, large current signals can pass. This signal can be AC or DC.
Not just 1mm, any line width can pass DC or AC signals.

Q: There is a packaged device, and there are 2 pins in the device that need to be connected to the live wire and neutral wire of 220V AC respectively. So how to deal with this power line when drawing the PCB? Are there any size requirements for pads, wires, etc.? Are there any protective measures required? Is it not possible to directly add pads to connect to the pin pads of the device?
A: It is best to mill a groove between the neutral wire and the live wire, and choose the thickness of the wire according to the current. When the current is large, you can put a tin layer on the wire, and the pad should be slightly larger.

Q: The grounding of the PCB circuit board design is also the negative pole. What is the difference between the grounding here and the AC grounding?

A: The concept of the circuit board ground is somewhat different from that of the power supply system. The power supply system refers to the earth, that is, the terminal with the same potential as the earth.

The ground in the circuit board is just a common terminal of a potential, which can be positive or negative, depending on the needs of the designer. It’s just that everyone is used to and assumes that the negative pole is the common terminal, that is, the ground. The circuit board ground is not necessarily connected to the earth.

But it must be connected to the earth when EMI filtering is required.

Q: Should all GNDs on the PCB board be connected? There is a terminal (screw type) with two terminals marked as V1+ and V1- on the PCB schematic. Should V1- be connected to the power supply ground? But I used a multimeter to measure why V3- is not connected to other GNDs on the board?

So how do you connect the ground and 10V of the power supply to the V1+ and V1- ends of the terminal?

A: Not all ground wires on the board are connected together. The ground wires are divided into analog ground and digital ground, just like the ground wire in DC and the ground wire in AC cannot be connected together. That is to say, there is a ground wire that is specifically used for power supply, and there is a ground wire that is specifically used for signals (shielding signal interference). These two ground wires cannot be connected together.
In addition, you mentioned V1+ and V1-, and V1- should not be considered a ground wire. Generally, the signal represented by this method is a differential signal, that is, the V1 signal is differentially divided into V1+ and V1-, which can reduce external interference and transmit farther. Finally, V1+ and V1- are integrated into the V1 signal.
You need to figure out whether the V1+ and V1- of the terminal are used for power supply. If they are used for power supply, then V1+ is the positive pole. V1- is the negative pole. Since you didn’t show us the picture, you can’t just connect it randomly. The circuit board needs to connect not only power but also signals, depending on how your board is made.

What are the holes in a PCB called?

What are the holes on PCB called? What are the holes in the circuit? The holes on PCB can be roughly divided into 3 types, screw holes (mounting holes), conductive holes (vias), and plug-in holes.

Screw holes: Screw holes are used for fixing.

Conductive holes: Conductive holes (also called vias) are used for conducting electricity just like circuits.

Plug-in holes: Plug-in holes are of course used to plug in various parts, such as diodes, transistors, capacitors, inductors, etc.

What is a through hole

What is a through hole? Through holes, also known as perforations, are holes in a PCB that go all the way through the board. Their main purpose is to provide electrical connections for component pins while allowing soldering on both sides of the board.

1.A via is a special through hole whose wall is metallized to achieve electrical connection between different layers on a circuit board. This type of hole is usually used to connect component pins to internal circuits, or to achieve electrical connection between different layers in a multi-layer PCB. Vias need to be metallized during the PCB manufacturing process, which usually includes drilling, desmearing, chemical copper plating, and electroplating.

2.Non-conducting holes are the opposite of through holes. Their hole walls are not metallized, so they do not have electrical connection functions. These holes are mainly used for mechanical fixation, heat dissipation or identification purposes. Non-conducting holes are relatively simple in the PCB manufacturing process, and only drilling operations are required.

What is a blind via?

A blind via is a hole that extends from one side of a PCB to a certain internal layer without penetrating the entire board. The emergence of blind vias is mainly due to the development of HDI technology, which provides circuit designers with greater flexibility and more compact layout. Blind vias are usually used to connect surface mount components (SMD) to internal circuit layers, or to connect circuits between different internal layers.

What are buried vias?

Buried vias are holes located inside the PCB that do not penetrate any side of the board. They are completely hidden inside the board and are used to connect circuits between different internal layers. Buried vias are especially useful in HDI boards because they can reduce the overall thickness of the board while maintaining electrical connections between internal circuits.

What is a microvia?

Microvia refers to a hole with a smaller diameter, usually at the micron level. The emergence of microvia technology enables PCB designers to achieve more complex circuit layouts in a smaller space. Microvias are often used in high-density, high-reliability electronic devices such as mobile phones and tablets. The manufacture of microvias requires high-precision drilling equipment and technology to ensure the accuracy and reliability of the holes.

What are Mounting holes？

What are Mounting holes?Locking holes are auxiliary holes used in the PCB manufacturing and assembly process to accurately locate and fix the circuit board. They are usually located at the edge or specific position of the PCB to ensure that the circuit board can be accurately aligned and fixed during manufacturing, testing and assembly. The locating holes do not participate in the connection of the circuit, but are essential to ensure the quality and performance of the circuit board.

What are Mounting holes？

What are thermal vias?

Thermal vias are holes designed specifically for heat dissipation, usually large and can run through the entire PCB or multiple layers. Their role is to reduce heat buildup on the circuit board by increasing surface area and air flow, thereby improving the stability and reliability of the device. Thermal vias are particularly important in high-performance, high-power electronic devices.

FAQ About board electronics with holes

How to solve the contradiction between manual routing and automatic routing of high-speed signals?

Most of the current powerful routing software’s automatic routing tools have set constraints to control the routing method and the number of vias. The routing engine capabilities and constraint setting items of various EDA companies are sometimes very different. For example, whether there are enough constraints to control the winding method of the serpentine, whether the routing spacing of the differential pair can be controlled, etc. This will affect whether the routing method generated by automatic routing can meet the designer’s ideas. In addition, the difficulty of manually adjusting the routing is also related to the capabilities of the routing engine. For example, the pushing ability of the routing, the pushing ability of the via, and even the pushing ability of the routing pair copper. Therefore, choosing a routing tool with strong routing engine capabilities is the solution.

Will adding test points affect the quality of high-speed signals?

As for whether it will affect the signal quality, it depends on the method of adding test points and how fast the signal is. Basically, the additional test points (not using the existing vias (via or DIP pins) as test points) may be added to the line or a small section of wire may be pulled out from the line. The former is equivalent to adding a very small capacitor to the line, while the latter is an additional branch. Both of these situations will have some impact on high-speed signals, and the extent of the impact is related to the frequency speed of the signal and the edge rate of the signal. The magnitude of the impact can be learned through simulation. In principle, the smaller the test point, the better (of course, it must meet the requirements of the test equipment) and the shorter the branch, the better.

Can you introduce some foreign technical books and data on high-speed PCB design?

Now the application of high-speed digital circuits includes communication networks and calculators and other related fields. In the communication network, the operating frequency of PCB boards has reached around GHz, and the number of layers is as many as 40 layers as far as I know. Due to the advancement of chips, the operating frequency of calculator-related applications, whether it is a general PC or server, has reached 400MHz (such as Rambus) or above. In response to the demand for high-speed and high-density routing, the demand for blind/buried vias, mircrovias and build-up process technology is gradually increasing. These design requirements can be mass-produced by manufacturers.

Does the design of rigid-flexible boards require special design software and specifications? Where can I undertake the processing of such circuit boards in China?

Can I use general PCB design software to design flexible printed circuits (Flexible Printed Circuit). The Gerber format is also used for FPC manufacturers to produce. Since the manufacturing process is different from that of general PCBs, each manufacturer will have its own restrictions on line width, line spacing, and aperture (via) based on their manufacturing capabilities. In addition, some copper foil can be laid at the turning point of the flexible circuit board for reinforcement. As for the manufacturer, you can search for “FPC” as a keyword on the Internet and you should be able to find it.

If the size of the circuit board is fixed, if the design needs to accommodate more functions, it is often necessary to increase the routing density of the PCB, but this may lead to increased mutual interference between the routings, and at the same time, the impedance cannot be reduced if the routing is too thin. Please introduce the techniques in the design of high-speed (>100MHz) high-density PCBs?

When designing high-speed and high-density PCBs, crosstalk interference does need to be paid special attention to because it has a great impact on timing and signal integrity. Here are a few things to note:

Control the continuity and matching of the characteristic impedance of the trace.

The size of the trace spacing. The spacing commonly seen is twice the line width. Through simulation, you can know the impact of trace spacing on timing and signal integrity and find the tolerable spacing. The results of different chip signals may be different.

Choose an appropriate termination method.

Avoid the same routing direction of the upper and lower adjacent layers, or even have traces overlapped up and down, because this kind of crosstalk is greater than the case of adjacent traces on the same layer.

Use blind/buried vias to increase the trace area. However, the production cost of the PCB board will increase. It is indeed difficult to achieve complete parallelism and equal length in actual implementation, but it should be done as much as possible.

In addition, differential termination and common mode termination can be reserved to mitigate the impact on timing and signal integrity.

The RF part, IF part, and even the low-frequency circuit part of the outdoor unit are often deployed on the same PCB. What are the material requirements for such PCB? How to prevent interference between RF, IF, and even low-frequency circuits?

Hybrid circuit design is a big problem. It is difficult to have a perfect solution.

Generally, RF circuits are laid out and wired as an independent single board in the system, and there will even be a special shielding cavity. Moreover, RF circuits are generally single-sided or double-sided boards, and the circuits are relatively simple. All of these are to reduce the impact on the distributed parameters of RF circuits and improve the consistency of RF systems. Compared with general FR4 materials, RF circuit boards tend to use high-Q substrates. The dielectric constant of this material is relatively small, the distributed capacitance of the transmission line is small, the impedance is high, and the signal transmission delay is small. In hybrid circuit design, although RF and digital circuits are made on the same PCB, they are generally divided into RF circuit area and digital circuit area, and laid out and wired separately. Shielding is used between ground vias and shielding boxes.

What is PCBA?

PCBA is the abbreviation of Printed Circuit Board Assembly, which refers to the process and product of installing and soldering all necessary electronic components on a PCB (printed circuit board) to form a complete functional circuit. PCBA is a key step in the production of electronic equipment. It provides a platform for electronic components to work in a coordinated manner, enabling the device to perform its intended tasks.

What is a PCBA component?

What is a PCBA component?

PCBA components refer to electronic components soldered on PCBs, including various components packaged in SMD patches and DIP plug-ins, such as integrated circuits IC, crystal oscillators, diodes, triodes, resistors, capacitors, transformers, digital tubes, connectors, inductors, etc. These components are the basis for realizing the hardware connection and program functions of PCBA boards. PCB designers will draw the corresponding circuit schematics according to the functions of the products and select appropriate components to realize the circuit functions.

PCBA process steps

PCBA process steps

The PCBA (Printed Circuit Board Assembly) assembly process mainly includes two processes: SMT (surface mount technology) and DIP (through-hole insertion technology). According to the size and type of electronic components, the assembly process can be divided into several common component assembly methods such as single-sided mounting, double-sided mounting, single-sided mixed mounting and double-sided mixed mounting.

Empty board loading: Arrange the PCB boards neatly, put them into the material rack, and send the PCB boards to the SMT production line through the automatic board loading machine.

‌2. Printing solder paste: Print solder paste on the pads on the PCB board where components need to be soldered to prepare for subsequent soldering.

3.Solder paste inspection: Check the quality of solder paste printing through optical instruments to ensure that there is no problem such as too much tin, too little tin or thick solder paste.

4.SMT: Use high-speed SMT machines and general-purpose SMT machines to attach electronic components to the PCB board. Small components use high-speed SMT machines, and large components use general-purpose SMT machines.

5.Reflow soldering‌: Melt the solder paste to solder the electronic components to the PCB board. Temperature control during the reflow soldering process is very important.

‌6. Cleaning and testing‌: Clean after soldering to remove excess solder and impurities, and then test to ensure that all components are correctly soldered.

PCB board inspection and acceptance standards

Appearance inspection: Check the dimensional accuracy, position accuracy, surface treatment and electrical safety of the PCBA board. The dimensional accuracy should meet the design requirements, such as aperture, line width, line spacing, etc. The position accuracy should be accurate and without deviation, such as component spacing, pad position, etc. The surface treatment should meet the requirements, such as whether there are scratches, oxidation, oil stains, cracks, depressions, discoloration, corrosion, etc. The electrical connection should be reliable, without short circuit or open circuit.

Acceptance conditions: The parts are damaged, but the body remains good, the internal metal components are not exposed, and the specifications are marked with text, and the polarity is identifiable. Although the IC is damaged, there is no cracking. There is no cracking between the IC foot and the body package. The part foot is not damaged. The part surface is tinned with a tin filling amount of more than 75% of the PCB board thickness. The pinhole size on the solder joint is less than 1/4 of the cross-sectional area of the part foot, and the pinhole at any point does not penetrate the PCB.

The difference between PCB and PCBA

PCB is the carrier and basic framework of electronic components, while PCBA is a circuit board assembly with specific functions, which directly determines the performance and function of electronic products.

Definition and Function

1.PCB (printed circuit board): It does not contain any active or passive components itself, but is just a basic framework.
Definition: PCB is a substrate used for electrical connection of electronic components, which forms a conductive circuit pattern on an insulating substrate through etching, drilling, copper plating and other processes.
Function: PCB mainly plays the role of supporting and electrically connecting electronic components, and is the carrier of electronic components.

2.PCBA (printed circuit board assembly) PCBA is the core part of electronic products and directly determines the performance and function of the product.
Definition: PCBA is a circuit board assembly with specific functions formed by soldering electronic components to PCB through processes such as SMT (surface mount technology) or THT (through-hole mounting technology).
Function: PCBA contains PCB and all necessary electronic components, which work together to realize the preset functions of the circuit board.

Manufacturing process

1.PCB manufacturing process
Design: Design the PCB layout according to the circuit schematic.
Making the substrate: Use materials such as copper foil, insulating materials and prepreg to make the substrate of the PCB.
Etching: Remove the unnecessary copper foil part on the substrate by chemical or physical methods to form a conductive circuit pattern.
Drilling: Drill holes on the PCB for connecting different layers or installing components.
Copper plating: Plate a layer of copper in the hole and on the surface of the circuit to improve conductivity and solderability.
Subsequent processing: Including steps such as cleaning, inspection, and cutting, and finally get the finished PCB.

2.PCBA manufacturing process
Preparation: Prepare the required PCB and electronic components.
Welding: Solder the electronic components to the PCB through SMT or THT technology.
Detection: Use automated testing equipment to perform functional testing and quality inspection on PCBA.
Packaging: Package qualified PCBA for transportation and storage.

Features and applications

1.PCB features
Customization: PCB can be customized according to specific needs to meet the layout requirements of different circuits and components.
Standardization: PCB manufacturing follows certain standards and specifications to ensure product quality and reliability.
Flexibility: PCB can adapt to various complex circuit designs and component layout requirements.
Widely used: PCB is widely used in various electronic products, such as mobile phones, computers, home appliances, etc.

PCBA features
Functionality: PCBA has specific functions and can be directly used for the assembly and testing of electronic products.
Integrity: PCBA contains all the necessary electronic components and PCBs, and is a complete circuit board assembly.
Reliability: After rigorous testing and inspection, PCBA has high reliability and stability.
Specific application: PCBA is usually used on the production line of electronic products and directly participates in the assembly and testing process of the product.

The difference between PCBA and SMT

PCBA VS SMT

There are significant differences between PCBA processing and SMT processing in terms of definition and scope, component types and assembly methods, process flow and equipment, application fields and product features.

Definition and scope
PCBA processing is a broader concept that covers the entire process of assembling electronic components onto printed circuit boards, including circuit board design, component selection, welding, testing and other links. PCBA processing can use both through-hole technology (THT) and surface mount technology (SMT).
SMT processing is an important link in PCBA processing, specifically referring to the process of mounting surface mount components (such as chip resistors, chip capacitors, etc.) on the surface of printed circuit boards using surface mount technology. SMT processing usually includes steps such as printing solder paste, mounting components, and reflow soldering.

Component types and assembly methods
PCBA processing can handle various types of components, including through-hole components (such as integrated circuits in DIP packages) and surface mount components. Through-hole components need to be soldered to the other side of the circuit board through the jack, while surface mount components are directly mounted on the surface of the circuit board.
SMT processing focuses on processing surface mount components. These components have the characteristics of small size, light weight, no pins or short pins, which can achieve high-density assembly, thereby improving the integration and performance of circuit boards.

Process flow and equipment
The application field of PCBA processing is very wide, covering almost all industries that require electronic circuit boards, such as communications, medical, aviation, home appliances, etc. Since PCBA processing can handle various types of components and complex assembly requirements, it is suitable for the production of electronic products of various sizes and complexities.
SMT processing is more suitable for the production of miniaturized, lightweight, and highly integrated electronic products. Since surface mount components are small and light, SMT processing can achieve high-density assembly, thereby reducing product volume and weight. In addition, SMT processing also has the advantages of high production efficiency and stable product quality.

PCBA Common Terms

Surface mount assembly (SMA): a printed circuit board assembly completed using surface mount technology.

Reflow soldering: the connection between surface mount components and PCB pads is achieved by melting the solder paste pre-allocated to the PCB pads.

Wave soldering: the molten solder is sprayed into a solder wave crest as required by the design through the equipment, so that the PCB with electronic components passes through the solder wave crest to achieve the connection between the components and the PCB pads.

Solder paste printing: the solder paste is placed on the steel mesh, and the solder paste is leaked through the holes on the steel mesh by a scraper and accurately printed on the PCB pads.

Automated optical inspection (AOI): the soldering effect of the PCB board can be detected by scanning and comparing. Defective PCB boards can be detected.

Rework: the act of reworking defective boards detected by AOI or manual inspection.

Fine pitch: refers to the lead center spacing of surface mounted package components ≤ 0.50mm.

‌Gerber file‌: A collection of document formats that describe circuit board images and drilling and milling data, used for PCBA quotation and processing.

‌BOM file‌: A bill of materials that lists all materials and quantities required for PCBA processing.

‌Solder paste deviation, solder paste tip, solder paste hole, etc.: These are common defects in PCBA processing.

FAQ About PCBA

FAQ Abaout PCBA

Why can PCBA processing improve the reliability and stability of circuit boards? PCBA processing can greatly reduce the failure rate of products, speed up the launch of products, and improve production efficiency through strict quality management system, strict control and quality inspection from component procurement to production process. ‌

How to ensure the quality of PCBA? The key to ensuring the quality of PCBA lies in a strict quality management system, including strict control and quality inspection from component procurement to production process. ‌

How to control the cost of PCBA processing? Methods to control the cost of PCBA processing include optimizing design, reducing component costs, and improving production efficiency. ‌

How to choose a suitable PCBA processing plant? Selecting a PCBA processing plant requires considering factors such as the factory’s equipment, quality management system, production capacity, and experience. ‌

What are the problems and causes of cold soldering in PCBA? Due to insufficient solder paste, insufficient soldering temperature, or too short soldering time, no effective soldering is formed between the component pins and the pads, which may cause circuit blockage or poor contact. ‌

What are the problems and causes of cold welding?
Due to the low welding temperature, the welding material is not completely melted, which is manifested as the surface of the welding point is rough, gray, and has no gloss. The welding strength is insufficient, which can easily cause the welding point to break.

What are the problems and causes of continuous welding?
Due to excessive application of solder paste or the pins of adjacent components are too close, a connection is formed between welding points that should not be connected, which may cause a short circuit.

What are the problems and causes of component damage?
Due to static electricity, overheating, mechanical stress and other reasons, the performance of components is reduced or completely fails, affecting the overall circuit function.

What are the problems and causes of component misalignment?
Due to equipment failure, operating errors and other reasons during the patch process, the components are not aligned with the pads on the PCB, which may cause poor welding or abnormal circuit function.

What are the problems and causes of PCB contamination?
During the production and storage process, it is polluted by oil stains, dust and other pollutants, which affects the welding effect and may cause problems such as poor welding or short circuit.

What are the problems and causes of PCB deformation?
Due to environmental factors such as high temperature and humidity, PCB deformation affects the mounting and welding of components, which may cause abnormal circuit function.

What are the problems and causes of missed inspection of PCBA?
Due to failure of detection equipment, operating errors, etc., defective products may flow into the next process or market, affecting product quality and customer satisfaction.

What are the problems and causes of PCBA mixing?
During the production process, components or PCBs are mixed, resulting in product performance not meeting requirements, which may cause customer returns or claims.

‌What is a high frequency pcb communication circuits

High frequency pcb communication circuits to a circuit board with an operating frequency in the high frequency band (usually greater than 300MHz or a wavelength less than 1 meter), which is mainly used to transmit high-frequency signals and data. ‌ This type of circuit board is widely used in radio frequency (RF) and microwave fields, such as communication equipment, radar systems, satellite communications, and high-speed data transmission systems.

What is a high frequency pcb communication circuits

The characteristics of high-frequency circuits include challenges such as transmission line effects, signal integrity issues, and electromagnetic interference (EMI). Due to the short wavelength of high-frequency signals, traditional low-frequency circuit design methods are no longer applicable, and special design and processing methods are required to ensure the performance and stability of the circuit.

High-frequency circuit boards are produced on microwave substrate copper-clad boards using ordinary rigid circuit board manufacturing methods or special processing methods. They need to have high-quality electrical properties and chemical stability to meet the requirements of high-frequency signal transmission.

Definition of high frequency pcb communication circuits

High-frequency circuit board, as a special circuit board, is mainly suitable for occasions with high electromagnetic frequency, especially in the fields of high frequency (frequency greater than 300MHz or wavelength less than 1 meter) and microwave (frequency greater than 3GHz or wavelength less than 0.1 meter).

It is a circuit board made on a microwave substrate copper-clad board by adopting some manufacturing processes or special processing methods of ordinary rigid circuit boards. Generally speaking, when the frequency of the circuit board reaches above 1GHz, it can be defined as a high-frequency board.

With the rapid development of science and technology, more and more equipment designs have begun to involve microwave frequency bands (>1GHz) and even expanded to the millimeter wave field (such as 77GHz), especially in popular applications such as 77GHz millimeter wave antennas on vehicles.

This trend not only promotes the continuous increase in frequency, but also puts higher requirements on the substrate of the circuit board.

For example, the substrate material needs to have excellent electrical properties, stable chemical properties, and as the frequency of the power signal increases, the loss on the substrate must be extremely small. Therefore, the importance of high-frequency boards is becoming more and more prominent.

Advantages of high frequency pcb communication circuits

The main advantages of high frequency pcb communication circuits include efficient data transmission, strong anti-interference ability, high-frequency bandwidth and high reliability. ‌

high frequency pcb communication circuits can achieve efficient data transmission. High-frequency signals have a short cycle and can transmit more information per unit time, so they have the advantage of large-capacity transmission. In addition, high-frequency signals can achieve fast signal processing and are suitable for application scenarios that require high-speed data transmission and high real-time requirements.
high frequency pcb communication circuits have strong anti-interference capabilities. Due to the short wavelength of high-frequency signals, they can better avoid external interference and attenuation and have strong anti-interference capabilities. This makes high-frequency signals have advantages in fields such as wireless communications and radar systems, and can achieve stable signal transmission and reception. ‌
high frequency pcb communication circuits also have the advantage of high-frequency bandwidth. High-frequency signals correspond to a larger frequency range and can provide higher bandwidth than low-frequency signals. This means that more data can be transmitted, thereby supporting higher data rates and richer media content. ‌
High reliability of high frequency pcb communication circuits is also one of its advantages. The use of high-quality materials and manufacturing processes can effectively resist external interference and oxidation corrosion, ensure stable performance in high temperature environments, and thus extend the service life of the circuit board.

Classification of high frequency pcb communication circuits

Classification by material:

Organic materials: including phenolic resin, glass fiber/epoxy resin, Polyimide, BT/Epoxy (bismaleimide triazine/epoxy resin), etc.
Inorganic materials: mainly including aluminum, copper-invar-copper, ceramic, etc. These materials are mainly selected for their excellent heat dissipation function.

Classification by the hardness of the finished product:

Rigid PCB: has a solid structure and stable performance.
Flexible PCB: has flexibility and bendability, suitable for occasions requiring flexible wiring.
Rigid-Flex PCB: It combines the characteristics of rigid and flexible boards, and has higher design flexibility and wide application.

Classification by structure:

Single-sided board: A circuit board with a conductive layer on only one side.
Double-sided board: Both sides are coated with conductive layers, separated by insulating materials in the middle.
Multilayer board: It is composed of multiple conductive layers and insulating layers, and has higher circuit integration and reliability.

Classification by use:

Communication board: It is used in various communication equipment and systems.
Consumable electronic board: It is commonly found in consumer electronic products.
Military board: A circuit board that meets special requirements in the military field.
Computer board: A circuit board used in computer hardware.
Semiconductor board: A circuit board used in the manufacturing and testing process of semiconductors.
Electrical test board: A circuit board used in electronic testing and measurement equipment.

How to choose high-frequency circuit board high-speed board

When choosing PCB board, you must find a balance between meeting design requirements, mass production and cost. In short, the design requirements cover two aspects: electrical performance and structural reliability. Especially when designing ultra-high-speed PCB (frequency greater than GHz), the choice of board is particularly important. For example, the commonly used FR-4 material will have a significantly increased dielectric loss (Df, i.e., Dielectric Loss) at a frequency of several GHz, and may no longer be applicable.

Taking the 10Gb/S high-speed digital signal as an example, this signal can be regarded as the superposition of multiple sinusoidal wave signals of different frequencies. Therefore, the 10Gb/S signal contains multiple components of different frequencies: such as a 5GHz fundamental signal, a 3rd-order 15GHz signal, a 5th-order 25GHz signal, and a 7th-order 35GHz signal. In order to ensure the integrity of digital signals, maintain the steepness of the upper and lower edges of the signals, and be compatible with the low-loss, low-distortion transmission of RF microwaves (the high-frequency harmonic part of the digital signal reaches the microwave frequency band), the selection of materials for high-speed digital circuit PCBs has many similarities with the needs of RF microwave circuits.

In actual engineering operations, the selection of high-frequency boards seems simple, but the factors that need to be considered are quite complex. Through the introduction of this article, PCB design engineers or high-speed project leaders can have a deeper understanding of the characteristics and selection of boards. Understand the electrical properties, thermal properties, reliability and other characteristics of the board, and use the stacking design reasonably to create products with high reliability and excellent processability, and achieve the best balance of various factors.

Composition and key components of high frequency pcb communication circuits

High frequency pcb communication circuits are basically composed of passive components, active devices and passive networks. Passive components include resistors, capacitors and inductors, which mainly exhibit resistance characteristics at low frequencies, but also exhibit reactance characteristics at high frequencies. Active devices such as high-frequency triodes have the characteristics of high gain, high frequency response and low noise, and are widely used in television, radio communication, radar and other fields.

Application of high frequency pcb communication circuits

High frequency pcb communication circuits are widely used in long-distance communication systems, with a communication distance of up to thousands of kilometers, and are often used to maintain communication between aircraft and bases. It occupies a high-frequency band of 2~30MHz, uses skywave propagation, and can propagate over long distances. Modern airborne high-frequency communication systems usually use single-sideband communication systems, which can greatly compress the occupied frequency band and save transmission power. However, high-frequency communication is also susceptible to electrical interference such as ionospheric disturbances and lightning, generating radio background noise, and there is fading, and the signal is sometimes strong and sometimes weak.

Design Guidelines for High Frequency PCB Communication Circuits

Design Guidelines

High Frequency PCB Communication Circuits

How to avoid high-frequency interference?

The basic idea of avoiding high-frequency interference is to minimize the interference of the electromagnetic field of high-frequency signals, which is the so-called crosstalk. You can increase the distance between high-speed signals and analog signals, or add ground guard/shunt traces next to analog signals. Also pay attention to the noise interference of digital ground to analog ground.

How to solve the signal integrity problem in high-frequency communication PCB design?

Signal integrity is basically an impedance matching problem. The factors that affect impedance matching include the architecture and output impedance of the signal source, the characteristic impedance of the trace, the characteristics of the load end, and the topology of the trace. The solution is to rely on termination and adjust the topology of the trace.

How is the differential wiring method implemented?

There are two points to note when wiring differential pairs. One is that the length of the two lines should be as equal as possible, and the other is that the spacing between the two lines (this spacing is determined by the differential impedance) should remain unchanged, that is, they should be kept parallel. There are two parallel methods, one is that two lines run on the same routing layer (side-by-side), and the other is that two lines run on two adjacent layers (over-under). Generally, the former side-by-side (side by side, shoulder to shoulder) is more commonly used.

How to implement differential routing for clock signal lines with only one output end?

To use differential routing, it must be meaningful if both the signal source and the receiving end are differential signals. Therefore, differential routing cannot be used for clock signals with only one output end.

Can a matching resistor be added between the differential line pairs at the receiving end?

The matching resistor between the differential line pairs at the receiving end is usually added, and its value should be equal to the value of the differential impedance. This will improve the signal quality.

Why should the routing of differential pairs be close and parallel?

The routing method of differential pairs should be appropriately close and parallel. The so-called appropriate proximity is because this spacing will affect the value of differential impedance, which is an important parameter for designing differential pairs. Parallelism is also required because the consistency of differential impedance must be maintained. If the two lines are sometimes far away and sometimes close, the differential impedance will be inconsistent, which will affect the signal integrity and timing delay.

How to deal with some theoretical conflicts in actual wiring?

Basically, it is right to separate the analog/digital ground. It should be noted that the signal routing should try not to cross the split place (moat), and the return current path of the power supply and signal should not be too large.

The crystal oscillator is an analog positive feedback oscillation circuit. To have a stable oscillation signal, the loop gain and phase specifications must be met. The oscillation specification of this analog signal is easily interfered. Even if ground guard traces are added, it may not be possible to completely isolate the interference. Moreover, if it is too far away, the noise on the ground plane will also affect the positive feedback oscillation circuit. Therefore, the distance between the crystal oscillator and the chip must be as close as possible.

It is true that there are many conflicts between high-speed wiring and EMI requirements. But the basic principle is that the resistors, capacitors or ferrite beads added due to EMI cannot cause some electrical characteristics of the signal to not meet the specifications. Therefore, first use the techniques of arranging routing and PCB stacking to solve or reduce EMI problems, such as routing high-speed signals on the inner layer. Only then use resistors, capacitors or ferrite beads to reduce damage to the signal.

How to solve the contradiction between manual routing and automatic routing of high-speed signals?

Most of the current powerful routing software’s automatic routing tools have set constraints to control the winding method and the number of vias. The winding engine capabilities and constraint setting items of various EDA companies are sometimes very different. For example, whether there are enough constraints to control the winding method of the serpentine, whether the routing spacing of the differential pair can be controlled, etc. This will affect whether the routing method generated by automatic routing can meet the designer’s ideas. In addition, the difficulty of manually adjusting the routing is also related to the ability of the winding engine. For example, the pushing ability of the routing, the pushing ability of the via, and even the pushing ability of the routing to the copper plating, etc. Therefore, choosing a routing tool with a strong winding engine capability is the solution.

About test coupon.

The test coupon is used to measure the characteristic impedance of the produced PCB board with TDR (Time Domain Reflectometer) to see if it meets the design requirements. Generally, the impedance to be controlled is single line and differential pair. Therefore, the trace width and line spacing (when there is a differential pair) on the test coupon should be the same as the line to be controlled. The location of the ground point during measurement is important. In order to reduce the inductance of the ground lead, the grounding point of the TDR probe is usually very close to the probe tip, so the distance and method between the point where the signal is measured on the test coupon and the ground point should be consistent with the probe used.

In high-speed PCB design, the blank area of the signal layer can be copper-plated, and how should the copper of multiple signal layers be distributed in grounding and power supply?

Generally, the copper plating in the blank area is mostly grounded. However, when plating copper next to high-speed signal lines, pay attention to the distance between the copper plating and the signal line, because the copper plating will reduce the characteristic impedance of the trace a little. Also be careful not to affect the characteristic impedance of other layers, such as in the dual strip line structure.

Can the signal line on the power plane be calculated using the microstrip line model? Can the signal between the power and ground planes be calculated using the stripline model?

Yes, both the power plane and the ground plane must be considered as reference planes when calculating the characteristic impedance. For example, a four-layer board: top layer-power layer-ground layer-bottom layer. At this time, the model of the characteristic impedance of the top layer routing is a microstrip line model with the power plane as the reference plane.

Can the automatic generation of test points on high-density printed circuit boards by software generally meet the test requirements of mass production?

Whether the test points automatically generated by general software meet the test requirements depends on whether the specifications for adding test points meet the requirements of the test equipment. In addition, if the routing is too dense and the specifications for adding test points are strict, it may not be possible to automatically add test points to each line. Of course, the places to be tested need to be filled manually.

Will adding test points affect the quality of high-speed signals?

As for whether it will affect the signal quality, it depends on the way of adding test points and how fast the signal is. Basically, the additional test point (without using the existing via or DIP pin as the test point) may be added to the line or a short line may be pulled out from the line. The former is equivalent to adding a very small capacitor to the line, and the latter is an additional branch. Both situations will have some impact on the high-speed signal, and the degree of impact is related to the frequency speed of the signal and the edge rate of the signal. The magnitude of the impact can be known through simulation. In principle, the smaller the test point, the better (of course, it must meet the requirements of the test equipment) and the shorter the branch, the better.

How should the ground wires between the boards of a system be connected when several PCBs are connected to each other?

When the signals or power supplies between the PCB boards are in operation, for example, when the power supply or signal from board A is sent to board B, there will be an equal amount of current flowing back from the ground layer to board A (this is Kirchoff current law). The current on the ground layer will flow back to the impedance. Therefore, at each interface where the power supply or signal is connected to each other, the number of pins allocated to the ground layer should not be too small to reduce the impedance, so as to reduce the noise on the ground layer. In addition, the entire current loop can be analyzed, especially the part with larger current, and the connection method of the ground layer or ground wire can be adjusted to control the flow of current (for example, create low impedance at a certain place to let most of the current flow through this place) to reduce the impact on other more sensitive signals.

What is pcba?

PCBA is the abbreviation of Printed Circuit Board Assembly, which means “circuit board assembly” or “circuit board assembly”. ‌It refers to installing electronic components on a printed circuit board and connecting the components to the circuit board through welding and other methods to form a complete circuit system.

This process involves multiple important links, including SMT (surface mount technology) mounting, DIP (dual in-line package) plug-in, etc., which eventually form a key component of electronic products. PCBA is not only the physical support of electronic equipment, but also provides a way to connect circuits, and also plays a role in protecting components and dissipating heat. In the manufacturing process of electronic products, the production process of PCBA includes steps such as PCB design, manufacturing, component placement, welding and testing to ensure the functionality and reliability of the product.

What does pcba stand for in electronics

PCBA stands for Printed Circuit Board Assembly in electronic products‌. PCBA is the process of assembling and soldering electronic components on a printed circuit board to form a complete circuit board. It is an important part of modern electronic products, including mobile phones, computers, cars, home appliances, etc.

. PCBA processing involves several important links, such as SMT (surface mount technology) and DIP (dual in-line package) plug-ins, which ensure the correct placement of electronic components and the reliability of the circuit. In addition, the use of PCBA processing equipment and the improvement of manufacturing processes, such as printers and dispensing machines, have improved the yield and efficiency of PCBA processing products‌

What is pcba manufacturing

The manufacturing process of PCB (printed circuit board) involves multiple process links, including design, plate making, drilling, filling, electroplating, etc. These steps together constitute the manufacturing process of PCB.

Design: First, according to the needs and layout design of the circuit, the circuit diagram is drawn using computer-aided design (CAD) software. This stage is very critical because it directly determines the function and performance of the PCB.
Plate making: After the design is completed, the designed circuit diagram needs to be converted into a practical PCB board that can be made. This usually involves the use of photosensitive materials and special chemical treatments so that the circuit pattern can be accurately transferred to the PCB substrate.
Drilling: After the plate making is completed, holes need to be drilled on the substrate according to the designed circuit pattern. These holes are used for subsequent wiring connections. The precision and accuracy of drilling are essential to ensure the normal operation of the circuit.
Filling: After drilling, some substances, such as resin, need to be filled in the hole to enhance the structural strength and electrical insulation performance of the PCB.
‌Electroplated‌: In order to ensure good electrical connection, the PCB needs to be electroplated, usually by electroplating a layer of copper or other conductive materials on the copper foil. This step is very important to ensure the conductivity and durability of the circuit.
‌Lamination and cutting‌: After the electroplating is completed, the multi-layer circuit boards are laminated together to form a multi-layer PCB. Subsequently, the PCB boards are cut into specific sizes as needed.
Inspection and testing‌: The manufactured PCB is inspected and tested to ensure that its functions and performance meet the design requirements. This may include visual inspection, functional testing and other methods.
‌Finished product assembly‌: The qualified PCBA board is assembled into the shell

‌What is the SMT process in PCBA?

‌1. Programming and adjusting the SMT machine‌: According to the information provided by the customer, program the coordinates of the location of the SMT components and perform the first piece check.

2. Printing solder paste‌: Use a screen printer to print the solder paste on the pads on the PCB board where the electronic components need to be soldered.

3. SPI inspection‌: Use a solder paste detector to detect the quality of solder paste printing to ensure that there are no defects.

4. SMT‌: Use a SMT machine to accurately install the electronic components SMD to the fixed position of the PCB.

‌5. High-temperature solder paste melting‌: The solder paste is melted at high temperature through a reflow oven to firmly solder the electronic components SMD and the PCB board together.

6. AOI inspection‌: Use an automatic optical inspection instrument to detect whether the PCBA components after welding have poor welding.

7. Visual inspection‌: Manual inspection checks the version of the PCBA, whether the direction of the components is correct, and the defects after welding.

8. Packaging‌: The qualified products are separated and packaged. The packaging materials used include anti-static bubble bags, static cotton, blister trays, etc.

PCB Assembly manufacturer High Quality & Fast Delivery

Best Technology is a PCB assembly manufacturer in Asia, who specializes in printed circuit board assembly (PCBA) and manufacturing. We have our own PCBA factory with 8 SMT lines, each line equipped with full-automated manufacturing and testing machine. In our PCBA factory, you can see dual-online AOI, SPI, X-RAY, nitrogen reflow oevn and so on. We are certified by ISO9001, ISO13485, and IATF16949, ensuring the highest quality standards in every PCB project.

Full turnkey service from pcb design, pcb manufacturing, component sourcing, pcb assembly, pcb duplicating in a very short time.

We source all the parts directly from the manufacturers or from authorized distributors such as Digikey, Mouser,Future,TTI,Avnet and Arrow to avoid counterfeit parts.

We also warehouse a significant inventory of common parts.If we cannot source a specific component, our engineers will make recommendations for fair-price alternatives.

What is pcba test

‌‌PCBA testing‌ is the process of testing the electrical conductivity and input-output values of the PCBA circuit board with mounted electronic components to ensure that all the installed circuit boards are completely consistent with the various specifications and parameters of the design. Through strict testing, the performance and reliability of the PCBA board can be improved, customer trust can be won, and cooperation between enterprises and customers can be promoted.

PCBA testing includes various test forms, such as ICT testing (internal circuit testing), FCT testing (functional testing), fatigue testing, extreme environment testing and aging testing.
ICT testing tests the characteristics of devices and circuit networks by applying test probes to the test points on the PCB.

FCT testing is mainly used to test the electronic and electrical functional aspects of the PCBA board, and is tested under the condition of simulating the actual operating state of the PCBA board. Fatigue testing performs high-frequency and long-term operations by sampling to observe whether failures occur.

Extreme environment testing places the PCBA board in harsh and extreme environments, such as high temperature, severe cold, and falling, to infer the reliability of the PCBA board. Aging testing is to power on the PCBA board and electronic products for a long time to observe whether any failures occur.

What is a pcba number

A combination of letters and numbers used to uniquely identify and track each electronic component on a circuit board. These numbers are often called component numbers, part numbers, or reference designators.

On PCBA boards, the format and meaning of these numbers may vary depending on the manufacturer and designer, but generally follow certain rules.

For example, common numbers are R107, C118, Q102, D202, etc., where:
The first letter usually identifies the type of device, such as: R for resistors, C for capacitors, D for diodes, Q for transistors, etc.
The subsequent digital part may indicate the circuit function number (such as “1” may indicate the motherboard circuit, “2” may indicate the power supply circuit, etc.) and the serial number of the device on the circuit board.

FAQ About PCBA

hat does poor welding include and what kind of faults will it cause?
Poor welding is manifested as incomplete solder joints, cold solder joints, etc., which lead to reduced conductivity of the circuit board or circuit failure. Solutions include optimizing soldering parameters, ensuring pad cleanliness, adjusting soldering energy, and increasing soldering temperature or extending soldering time.

What causes component misalignment?
It is caused by inaccurate positioning of components during the soldering process, affecting circuit connection and product function. Solutions include implementing precise visual inspection and automatic inspection to ensure that components are placed correctly and rework and repair.

What do short circuits and open circuits mean?
Short circuits and open circuits: caused by poor insulation or fracture between adjacent solder joints on the circuit board or between solder joints and lines, which may cause abnormal current flow or circuit interruption. Solutions include ensuring that solder paste is evenly applied, components are correctly placed, and adjusting soldering parameters to avoid excessive soldering temperature and pressure.

What causes solder cracking?
Solder cracking: cracking occurs during use or after a certain environmental stress, usually due to excessively high temperatures, long soldering time, or improper selection of soldering materials during the soldering process. Solutions include optimizing soldering parameters, ensuring proper soldering temperature and time, and selecting appropriate soldering materials.

Why electrostatic discharge?
‌Electrostatic discharge (ESD) damage: Sensitive electronic components can be damaged by ESD. Solutions include implementing ESD control measures in the production environment, such as using ESD gloves and anti-static workbenches.
Does voltage instability affect PCBA performance?
‌Power supply issues: Power supply stability issues can affect PCBA performance. Solutions include implementing power electronics technology and voltage regulators to ensure stable power supply.

what does pcba stand for

PCBA stands for Printed Circuit Board Assembly. Other synonyms of PCBA include “PCB Assembly”, “Populated PCB” and “Board Assembly”. These terms are widely used in the electronics industry to describe the finished or semi-finished state of a circuit board after component placement and soldering.‌

what is a pcba board

PCBA board, full name Printed Circuit Board Assembly, Chinese name is printed circuit board assembly, refers to the installation and welding of components on the completed printed circuit board to form a circuit board that can be used directly.

The production process of PCBA board mainly includes three steps: component mounting, welding and testing. First, the obtained components are accurately positioned and mounted on the PCB board according to the design requirements, and then the components are firmly fixed on the PCB board by welding, and the circuit is ensured to be unobstructed. Finally, the circuit is tested to verify whether it is working properly. The whole process requires a high degree of technology and precision to ensure the quality of PCBA board.

Usb connector types

Types of USB connectors: different types of connectors with different shapes and directions, USB connectors can be separated into different types:

Type-A port: This is the most common type of USB port, the shape is long and rectangular, and the support is heat-resistant. Computer equipment such as printing machine, keypad, mouse button, driving device, etc. Type-A interface has USB 2.0 and USB 3.0 in different editions, among which USB 3.0 has faster speed, color is usually blue, and USB 2.0 has slow speed, color is black.

Type-B contact: Type-B contact shape is round shape, demand-specific connection. For general use, external equipment such as audio equipment, viewing equipment, etc., such as a 3.5 inch movable screen, stamping machine, display device, etc.Type-B verbal usage scene is relatively small, so this is an unusual sight in daily life.

Usb connector types:Type-A port:Type-B contact

Type-C port: Type-C port is a new type of USB port that has emerged in recent years. Built-in USB 3.1, Type-C interface configuration, mainstream interface type, intelligent handheld computer, flat panel battery, notebook battery, etc. The biggest feature of the Type-C interface is its support and double-sided insertion, making it convenient and convenient to use.

Type-C interface support further improves the speed and power of the power, and provides more advanced usage experience. Previously, when I came here, I was confused as to how to get around the main machine.

Mini USB port Micro USB port

Mini USB port Micro USB port: There are many types of ports for transfer equipment, digital reading machine, digital image machine, metering equipment, etc. Mini USB port ratio Micro USB port size is small, also known as a USB port, Micro USB port is smaller, thinner, supports OTG function, and provides a number of additional power functions. The Micro USB port is convenient and easy to use, and has various types of portability.

What functions does USB have?

Power Delivery of USB Ports
Some USB cables can deliver power as well as transfer data, but most USB cables can do both. Power delivery of USB ports is mainly divided into three categories: fast charging, quick charging, and power only.
USB Data Transfer Speed
USBs come in various sizes and shapes. Also, USB types have multiple speed standards. It is important to know that some USB cables are designed for data transfer only, while some can only deliver power. However, some USB cables can serve both purposes at the same time. Therefore, it is necessary to verify the performance of the cable before purchasing it.
USB Video Transfer
The ability of USB ports to power devices and transfer data between devices is already impressive enough. However, you can decide to integrate USB-C to connect a monitor in place of a VGA cable or HDMI. In addition, USB-C also supports 4K video transmission.

What are the advantages of USB interface?

Standard uniformity. The most common ones are hard disks with IDE interfaces, mouse and keyboards with serial ports, and printers and scanners with parallel ports. However, with USB, all these application peripherals can be connected to personal computers using the same standard. At this time, there are USB hard disks, USB mice, USB printers, etc.
Easy to carry. Most USB devices are known for being “small, light, and thin”, which is very convenient for users to carry large amounts of data with them.
Hot-swappable. That is, when users use external devices, they do not need to shut down and restart the computer, but directly plug in the USB when the computer is working.
Multiple devices can be connected. USB often has multiple interfaces on personal computers, and several devices can be connected at the same time. If a USB HUB with four ports is connected, four USB devices can be connected, and so on. You can connect all the devices to a personal computer at the same time without any problems (up to 127 devices can be connected).

How Do USB Ports Work?

USB is an external bus standard used to regulate the connection and communication between computers and external devices. The USB interface has plug-and-play and hot-swap functions. The USB interface can connect 127 peripherals, such as mice and keyboards. USB was jointly launched by Intel and other companies in 1994 and has successfully replaced serial and parallel ports since 1996. It has become a must-have interface for computers and a large number of smart devices today. For most engineers, the main obstacles to developing USB2.0 interface products are: facing the complex USB2.0 protocol, writing USB device drivers by themselves, and being familiar with microcontroller programming.

Why USB Ports Are Replacing Serial Ports

USB has three major advantages. It is superior to serial ports in several aspects.

Speed
USB ports are able to transfer data at a much faster speed. They work ten times faster than regular parallel ports. Also, they are much faster than serial ports. On average, serial ports offer a data transfer rate of 150kbps. On the other hand, USB ports offer about 12 Mbps. The data transfer rate depends on the type of USB port. For example, USB 2.0 has a maximum data transfer rate of 480 Mbps.

Compatibility
USB ports have replaced serial ports in the past few years. Various industrial devices are equipped with serial ports. This replacement has brought problems. USB ports are generally compatible with most USB devices.

Durability
USB ports are more durable than serial ports. The tiny pins on a serial port can break or bend easily. Whereas USB ports are very sturdy.

Frequently Asked Questions

The USB interface cannot be used. It may be due to a problem with the system. You need to check whether the system service is disabled or reinstall the operating system.

‌BIOS setting problem‌. If USB is disabled in BIOS or CMOS, you need to restore it to the factory default settings.

‌USB driver is not installed or the driver is deleted‌. You need to install the USB universal driver.

‌The front USB cable is not connected properly‌. Try to insert the USB flash drive into the USB interface on the back of the chassis.

‌The USB interface voltage is insufficient. When the mobile hard disk is connected to the front USB interface, it may not be recognized due to insufficient voltage. You should use a hard disk box with an external power supply or replace the power supply.

‌Compatibility issues between the motherboard and the system‌. For example, the compatibility issues between the NF2 motherboard and USB require the installation of the latest dedicated USB2.0 driver and patch.

‌System or BIOS problem‌. When USB is disabled in the BIOS or operating system, you need to enable options related to USB devices.

‌Be careful when plugging and unplugging. Do not unplug during reading and writing, otherwise the chip may be burned.

‌If the USB device is frequently disconnected‌, it may be that the USB cable connection is unstable or there is a problem with the USB port. Try changing the cable or connecting to another USB port.

‌If the USB device cannot be recognized or charged‌, make sure the device is compatible and the cable is intact. Try connecting to another computer or updating the driver.

What is an Amplifier Board?

An amplifier board is an electronic circuit designed to amplify audio signals. It takes a low-power input signal, such as the sound from a music player, and increases its strength to a level that can drive speakers or other audio output devices effectively. This amplification process ensures that the sound is louder and clearer when played through the speakers.

Amplifier boards are commonly used in various audio applications, including home theater systems, car audio setups, and professional sound equipment. They are essential for delivering high-quality audio performance, especially in environments where louder sound output is needed. Amplifier boards come in different types, each suited for specific applications, and are designed to handle various power levels and sound quality requirements.

What is an Amplifier Board? – Definition, Types, Uses

What Does an Amplifier Board Do?

An amplifier board serves the crucial function of boosting the power of audio signals. In any audio system, the original signal generated by a source, such as a smartphone, MP3 player, or microphone, is usually weak. This weak signal is insufficient to drive speakers or produce audible sound at a volume that is satisfactory. The amplifier board steps in to enhance this signal, increasing its power so that it can drive speakers effectively.

Beyond simply making the sound louder, a well-designed amplifier board ensures that the audio signal remains clear and free from distortion throughout the amplification process. This means that whether you’re listening to music, watching a movie, or using a public address system, the sound you hear is rich, clear, and true to the original input.

Amplifier boards are versatile and can be found in various settings, from home audio systems and portable Bluetooth speakers to car audio systems and professional sound equipment. Each of these applications demands different levels of power and sound quality, and amplifier boards are designed to meet these specific needs.

Types of Amplifier Boards

Wiring Harness
2 Channel Stereo Amp
Battery & Power
1 Channel Mono Amp
2.1 Channel Amp
Interface
Preamp
4 Channel Amp
Bluetooth / Wi-Fi Receiver
Panels & Mounting Acc.
Panels & Mounting Acc.-Wiring Harness
10 Channel Amp
3 Channel Amp
6 Channel Amp

What Is the Function of the Amplifier?

The primary function of an amplifier is to increase the amplitude of an audio signal, making it strong enough to drive loudspeakers and other audio output devices. An amplifier takes in a low-power audio signal, processes it, and outputs a much stronger signal without significantly altering the original sound’s characteristics.

This function is crucial in ensuring that the sound produced by the speakers is loud enough to fill a room, stadium, or outdoor space, depending on the application. For example, in a home theater system, the amplifier ensures that the dialogue, music, and sound effects are all heard clearly, even during quieter scenes or moments of intense action.

In addition to boosting the signal, amplifiers often have other functions, such as controlling volume, adjusting equalization (bass, treble, midrange), and managing different audio inputs. This makes the amplifier a central component in any audio system, responsible for not just increasing volume but also enhancing overall sound quality.

What Kind of Amplifier Do I Need for Speakers?

Choosing the right amplifier for your speakers involves considering several factors, including the power rating of the speakers, their impedance, and the environment in which they’ll be used. The goal is to find an amplifier that can provide sufficient power to drive the speakers without overpowering them.

1. Matching Power Rating

The amplifier’s power output should generally match the speaker’s power handling capacity. For instance, if your speakers are rated at 100 watts, you’ll want an amplifier that can deliver 100 to 150 watts per channel. This ensures that the amplifier can drive the speakers efficiently without causing distortion or damage.

2. Impedance Compatibility

Speakers have an impedance rating, usually measured in ohms, that the amplifier must match. Common impedance values are 4, 6, or 8 ohms. The amplifier should be capable of driving the speaker’s impedance; otherwise, it may overheat or fail to deliver optimal sound quality.

3. Application and Environment

Consider where and how the speakers will be used. For a small room, a lower-powered amplifier might be sufficient, while larger spaces or outdoor settings may require a more powerful amplifier. If you’re setting up a home theater system, you might need an amplifier that supports multiple channels to handle different speakers in a surround sound configuration.

4. Sound Quality Preferences

If you’re an audiophile or someone who values high-quality sound, you might opt for an amplifier that prioritizes sound fidelity, such as a Class A or Class AB amplifier. For more general purposes or where efficiency is key, a Class D amplifier might be more suitable.

What Is the Difference Between a Mixing Board and an Amplifier?

A mixing board, also known as an audio mixer, combines multiple audio signals into one or more outputs. It allows you to adjust levels, EQ, and other parameters for each input channel. On the other hand, an amplifier boosts the power of the audio signal to drive speakers. While a mixing board controls the audio mix, an amplifier ensures that the mix is loud enough for playback through speakers.

What Is the Main Advantage of an Amplifier?

The main advantage of an amplifier is its ability to enhance audio signals, allowing them to be played at higher volumes while maintaining sound clarity and fidelity. This is particularly important in situations where audio needs to be heard clearly over background noise or across large distances.

1. Loudness and Clarity: Amplifiers ensure that audio signals are strong enough to drive speakers and produce sound at desired volume levels. This is essential for ensuring that music, speech, and other audio content are heard clearly, whether in a small room, a large auditorium, or an outdoor event.

2. Improved Sound Quality: A well-designed amplifier can improve the overall sound quality of an audio system by minimizing distortion and noise, ensuring that the output remains true to the original recording.

3. Versatility and Control: Amplifiers often come with features that allow users to control various aspects of the audio signal, such as volume, balance, and equalization.

What Happens if an Amp is Too Powerful for Speakers?

Using an amplifier that is too powerful for your speakers can result in speaker damage. When an amplifier delivers more power than the speakers can handle, it can cause the speaker components to overheat or even blow out. It’s essential to match the amplifier’s power output to the speaker’s power rating to avoid such issues. Always refer to the manufacturer’s specifications to ensure compatibility.

How Many Watts is Good for a Speaker?

The appropriate wattage for a speaker depends on the intended use and the size of the space in which it will be used. For small rooms, speakers with a power rating of 20 to 50 watts per channel may suffice. For larger spaces or outdoor use, speakers rated at 100 watts or more per channel are recommended. It’s important to match the amplifier’s power output to the speaker’s rating to ensure optimal performance and longevity.

What is the Basic Use of an Amplifier?

An amplifier’s basic use is to boost the power of audio signals so that they can drive loudspeakers effectively. Without amplification, the audio signal would be too weak to produce a meaningful sound output from the speakers. Amplifiers are used in various audio systems, including home theaters, car audio systems, and public address systems, to ensure that the sound is loud and clear.

Which Class Amplifier is Best for Sound Quality?

For sound quality, Class A amplifiers are often considered the best. They provide a consistent and high-quality output, making them ideal for high-fidelity audio systems. However, they are less efficient and generate more heat compared to other classes. For a balance between sound quality and efficiency, Class AB amplifiers are a popular choice, offering good sound quality while being more power-efficient than Class A.

Does an Amplifier Improve Sound Quality?

Yes, an amplifier can improve sound quality, especially when it’s well-matched to the speakers and the rest of the audio system. A good amplifier ensures that the audio signal is amplified without introducing distortion or noise. It also provides the necessary power to drive speakers, allowing them to perform at their best. However, it’s important to choose an amplifier that complements your audio setup to achieve the best sound quality.

Amplifier Board HS Code

The Harmonized System (HS) code for amplifier boards varies depending on the specific type and application. Generally, amplifier boards fall under the category of electronic integrated circuits or modules, which are typically classified under HS code 8542.90. However, it’s advisable to consult with a customs expert or refer to your country’s specific tariff schedule for precise classification.

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