Archive for the ‘HDI PCB’ Category

Special PCB Design, Prototype, Special PCB Manufacturer

Tuesday, March 18th, 2025

Special PCB is a customized circuit board designed for unique applications where standard PCBs do not meet the required performance, durability, or environmental conditions. These PCBs are used in industries such as aerospace, medical, telecommunications, and automotive, where factors like heat dissipation, high frequency, and miniaturization are crucial. Whether it’s a high-speed PCB, HDI PCB, or heavy copper PCB, each type serves a specific purpose to enhance electronic performance.

Best Technology excel in providing customer-centric support in PCB industry. The team offers special PCB design optimization, material selection guidance, and manufacturing feasibility analysis to the customers. Whether you need a special PCB prototype or full-scale special PCB manufacturing, just feel free to reach out to us at sales@bestpcbs.com, we work closely with you to meet your exact specifications.

Special PCB Design, Prototype, Assembly, Special PCB Manufacturer

What is Special PCB?

A special PCB is a customized printed circuit board that differs from standard PCBs in design, materials, or functionality. It is engineered to meet specific requirements such as high power handling, extreme temperatures, or unique form factors. These boards ensure stability, reliability, and efficiency in demanding applications.

What Are the Different Types of Special PCBs?

Special PCBs can be classified into three main categories based on their materials, functionality, and structure.

1) Material-Based Special PCBs

These PCBs are defined by the materials used to enhance their performance under specific conditions.

Heavy Copper PCB – Uses thick copper layers (≥3 oz) for high current applications and improved thermal management.

High Tg PCB – Made with high glass transition temperature (Tg) materials to withstand extreme heat and mechanical stress.

2) Function-Based Special PCBs

This category includes PCBs designed for specific electrical or performance characteristics.

High-Speed PCB – Designed with low-loss materials and controlled impedance for fast signal transmission in networking and computing.

Impedance Control PCB – Maintains precise impedance levels for RF, microwave, and high-frequency circuits.

RF Board – Uses low-loss materials to minimize signal interference in wireless communication, radar, and satellite applications.

Bus Bar PCB – Incorporates embedded copper bars for high current carrying capacity in power distribution systems.

3) Structure-Based Special PCBs

These PCBs are categorized based on their physical design and layout innovations.

HDI PCB – Features microvias, fine traces, and multiple layers for compact, high-density applications like smartphones and laptops.

Extra Thin PCB – Ultra-thin boards designed for compact and flexible electronic devices.

IC Substrate – Specialized interconnects used to bridge semiconductor chips with larger PCB assemblies.

What Materials Are Used to Make Special PCBs?

The choice of materials in special PCBs determines their electrical performance, heat resistance, and mechanical durability. Here are the key materials used:

1) FR-4

A fiberglass-reinforced epoxy laminate that offers a balance of cost, durability, and electrical insulation. It is commonly used in High Tg PCBs, HDI PCBs, and Impedance Control PCBs where thermal resistance and signal integrity are crucial.

2) High-Tg FR-4

An advanced version of FR-4 with a higher glass transition temperature (Tg), making it suitable for High Tg PCBs and High-Speed PCBs that operate under extreme thermal conditions.

3) Polyimide

This material provides exceptional thermal stability and flexibility. It is widely used in Extra Thin PCBs and HDI PCBs, where space-saving and durability under heat are essential.

4) PTFE (Teflon)

A low-loss, high-frequency material that is ideal for RF Boards and High-Speed PCBs. Its excellent dielectric properties help maintain signal integrity in wireless and microwave applications.

5) Copper

Heavy Copper PCB – Uses thick copper layers (≥3 oz) to support high current loads and enhance heat dissipation.
Bus Bar PCB – Features embedded copper bars for efficient power distribution in industrial and automotive applications.

6) BT (Bismaleimide Triazine) Epoxy Resin

This material is used in IC Substrates for its excellent electrical insulation, high-temperature resistance, and mechanical strength. It ensures reliable connections in semiconductor packaging.

7) Low-Dk (Low Dielectric Constant) and Low-Df (Low Dissipation Factor) Materials

These are specialized dielectric materials used in Impedance Control PCBs and High-Speed PCBs to reduce signal loss and maintain consistent impedance for high-frequency applications.

How to Design a Special PCB?

1) Define Requirements

Start by determining the electrical, thermal, and mechanical specifications needed for the application.

2) Select Materials

Choose the right substrate, copper thickness, and surface finish based on operating conditions and performance needs.

3) Create a Schematic

Develop a circuit diagram to define component placement and electrical connections.

4) Layout Design

Optimize routing, layer stack-up, and impedance matching to ensure signal integrity and manufacturability.

5) Prototyping & Testing

Before mass production, test a prototype to validate functionality, thermal management, and reliability.

What Are the Benefits of a Special PCB?

1) High Performance

Custom designs ensure superior electrical and thermal efficiency.

2) Enhanced Durability

Robust materials and specialized coatings increase lifespan, even in harsh environments.

3) Miniaturization

Advanced designs, such as HDI and extra thin PCBs, enable compact, lightweight devices.

4) Reduced Signal Loss

Impedance control and RF materials enhance signal integrity, crucial for high-speed and wireless applications.

What Are the Applications of Special PCBs?

1) Aerospace & Defense

Used in satellite systems, avionics, and military-grade electronics that require reliability under extreme conditions.

2) Automotive Electronics

Essential for EV power systems, engine control units, and ADAS (Advanced Driver Assistance Systems).

3) Medical Devices

Supports high-precision diagnostic equipment, wearable health monitors, and implantable devices.

4) Telecommunications

Used in 5G infrastructure, networking hardware, and high-speed data transmission systems.

Why Choose Best Technology as Your Special PCB Manufacturer?

1) Industry Expertise

With 18 years of experience, Best Technology specializes in manufacturing high-quality special PCBs tailored to unique requirements.

2) Multi-Variety PCB Manufacturing

Electronics manufacturers often require diverse PCB types within a single project. Best Technology offers a wide range of special PCBs, including Heavy Copper, Bus Bar, High-Speed, IC Substrate, Impedance Control, Extra Thin, High Tg, HDI, and RF Boards. Our ability to handle multiple PCB types under one roof simplifies the supply chain, reduces lead times, and ensures consistency across different PCB designs.

3) High Quality

Each special PCB undergoes rigorous testing to meet international quality and reliability standards.

4) Custom Solutions

As a leading special PCB manufacturer, we offer complete customization based on your project needs from special PCB design to special PCB assembly. Not only provide top quality requirements of Special Printed circuit Board and PCBA service for the market but also meet customer special customized requests.

Small-Batch Production

At Best Technology, we specialize in low-volume special PCB manufacturing, ensuring that even small orders receive the same level of precision and quality as mass production. This allows customers to test new designs, reduce risks, and accelerate product development.

FAQs Of Special PCB

1. What is the maximum operating temperature for PCBs?
Typically, the working temperature for standard PCB materials is 105-130°C. For high-temperature materials, such as those made with 7316D, the working temperature can reach 150-170°C. However, this material requires a higher MOQ.
2. Is the smallest copper trace width you can do 4mil?
Yes.
3. What PCB material brands do you use?
We use brands like Shengyi, KB, ITTEQ, GDM, and etc.
4. What is the maximum board size you can produce?
The maximum size we can produce is 610mm x 610mm.
5. What is the maximum copper thickness for a PCB?
We can produce a maximum copper thickness of 30oz (1050um).

In conclusion, special PCBs are essential for high-performance, reliable, and efficient electronic applications. Whether you need heavy copper PCBs for power applications or HDI boards for miniaturized devices, selecting the right manufacturer is crucial. Best Technology provides industry-leading expertise, top-notch quality, and tailored solutions to ensure your project’s success. Pls feel free to contact us at sales@bestpcbs.com to get started on your special PCB requirements!

Tags:PCBA, Special PCB, Special PCB Assembly, Special PCB design, Special PCB Manufacturer, Special PCB Prototype, Special Printed circuit Board
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Annular Ring: What is Annular Ring PCB? How to Calculate it?

Thursday, February 20th, 2025

Annular rings are small but essential features form part of the vias, helping to create electrical connections between different layers of the PCB. In simple terms, the annular ring is the copper ring that surrounds the hole in a PCB, and its quality can determine the effectiveness of the entire board. If not designed or manufactured correctly, the annular ring can lead to issues such as unreliable connections, potential failure, or even defective PCBs. In this blog, you’ll learn the importance in PCB design and functionality, how to calculate it correctly to avoid common issues occurred during PCB manufacturing.

What is Annular Ring in PCB?

To understand the importance of the annular ring, let’s break down its role in a PCB. A PCB is composed of multiple layers, and the annular rings on a PCB are circular metal rings used for mounting components on the circuit board. Sometimes, it also called PAD. They serve as connection points for the leads of electronic components and are attached to the corresponding positions on the board via soldering or insertion.

Annular Ring: What is Annular Ring PCB? How to Calculate it?

The annular rings are typically made of copper or other conductive materials, forming a connection around the holes to ensure that electrical signals can pass from one layer to another. Without this copper ring, the via would lack the necessary conductive material to transmit electrical signals, leading to potential functionality and reliability issues.

PCB holes usually come in shapes such as circular, square, or oblong. Among these, the circular hole is the most common. These holes are used for mounting components, connecting wires between circuit layers, or linking pads across different layers. When designing a PCB, you can select the appropriate hole shape based on specific needs.

What is an Annular Ring in Physics?

While the concept of the annular ring in PCB manufacturing is straightforward, it’s also rooted in basic physics. In physics, an annular ring is a two-dimensional geometric shape characterized by an outer and inner radius, with the space between the two radii representing the actual “ring.” This geometric shape has applications in a variety of fields, from fluid dynamics to optics.

In the context of PCB design, the annular ring’s geometry ensures that there’s enough copper material around the hole to support electrical connections and mechanical integrity. Essentially, the annular ring in PCB design mirrors this physical concept, providing the necessary structure to allow electrical signals to flow reliably between layers.

What is the Function of an Annular Ring?

The primary function of an annular ring is circuit connection. The annular ring connects with other circuit layers or components via wires or pins, enabling the transmission and interaction of electrical signals. Without this ring, the via would not have any conductive material to establish the necessary connections, rendering it ineffective. Essentially, the annular ring is like a bridge that connects different parts of the PCB. In addition to this, there are some other functions that apply annular rings in a PCB:

1. Component Mounting

The annular ring is used to secure and connect electronic components (such as integrated circuit chips (IC), diodes, resistors, etc.) to the PCB through their leads or solder balls.

2. Soldering Connection

The metal edge of the annular ring is used for soldering the leads or pads of electronic components, establishing a reliable electrical connection. Through soldering, a physical and electrical bond is created between the component and the PCB.

3. Vias in Multi-Layer PCBs

In multi-layer PCBs, the annular ring serves as a via, acting as a conductive channel that connects different circuit layers. Through these vias, signals, power, and ground lines can be transmitted between layers.

What is the Difference Between Via and Annular Ring?

While vias and annular rings often work in tandem, they are different components of a PCB.

Via:

A via is a drilled hole in the PCB, gennerally <=0.5mm.
It is plated with copper to create an electrical pathway.
Vias provide vertical connectivity between PCB layers.
They act as the conduits for electrical signals across layers.

Annular Ring:

An annular ring is the copper pad that surrounds the via.
It creates a stable landing zone for the via.
The annular ring enhances solderability and connection strength.
It also supports the mechanical integrity of the PCB.

Key Differences:

A via is the actual hole that allows electrical passage; the annular ring is the copper area around that hole.
Vias serve as internal conductive channels, while annular rings ensure a robust link to the board’s traces.
Vias are created by drilling and plating; annular rings are defined during the PCB layout design.

In essence, the via acts as a hole or passage for electrical signals, while the annular ring is the surrounding copper that ensures the electrical signals can flow reliably between the different layers of the PCB. Without the annular ring, the via would have no copper to connect it to the surrounding traces, compromising the integrity of the circuit board.

How Do You Calculate the Annular Ring Size?

The annular ring size is determined by the diameter of the via hole and the size of the copper pad around it. To calculate the annular ring size, you need to first measure the diameter of the via hole. Then, you need to determine the size of the copper pad around the hole, keeping in mind that the pad must be large enough to maintain a reliable connection. In general, there are outer annular ring size and inner annular ring size:

Outer Annular Ring Size (OAR)

Calculate Format:

Outer Annular Ring (OAR) = (Outer pad diameter – Plated hole diameter) / 2

Actual Case:

Plated hole diameter = Finished hole diameter + 0.10mm (for all PTH) + 0.00mm (for all NPTH).

Example:

For a copper pad thickness of 0.60mm and a finished hole diameter of 0.30mm (PTH), the calculation of the OAR is:

OAR = [0.60mm – (0.30mm + 0.10mm)] / 2 = 0.10mm

Inner Annular Ring Size (IAR)

Calculate Format:

Inner Annular Ring (IAR) = (Inner pad diameter – Electroplated hole diameter) / 2

Actual Case:

Electroplated hole diameter = Finished hole diameter + 0.10mm (for all PTH) + 0.00mm (for all NPTH).

Example:

For a 0.50mm copper pad and a 0.20mm finished hole diameter (PTH), the calculation of the IAR is:

IAR = [0.50mm – (0.20mm + 0.10mm)] / 2 = 0.10mm

What is the Minimum Annular Ring Size on a PCB?

The minimum annular ring (AR) on a PCB refers to the minimum amount of copper between the edge of the pad and the electroplated hole. The width of the minimum annular ring should be greater than or equal to the value defined in the PCB design.

When the annular ring is smaller than the specified width, the attachment of components may be affected, and there is a risk of pad cracking. In this case, the circuit may enter the pad, minimizing the current-carrying capacity of the circuit.

Sometimes, the traces on the PCB need to connect to another layer. In such cases, the trace eventually passes through the pad. The via in the pad helps the trace move through and connect to another layer.

t1: Minimum outer annular ring, on finished boards, must be >= 0.05mm.
t2: Minimum inner annular ring, on finished boards, must be >= 0.01mm.

Common Annular Ring Issues During PCB Manufacturing

Despite the importance of annular rings, issues can arise during the manufacturing process that impact their effectiveness. Some common problems include:

Undesired Annular Rings

Undesired annular rings are a common issue that affects many designers when working with standard PCBs. If the pad size is too small, the PCB may not function properly because the hole takes up more space on the pad. To avoid this issue, making a prototype before mass production is necessary. Prototypes can prevent unnecessary annular rings from appearing before large-scale production of the circuit boards.

Missing Annular Ring

A missing annular ring can occur if the design does not include an annular ring around the via, or if the annular ring was not correctly produced during manufacturing. This can lead to poor electrical connections, affecting the performance of the circuit.

Broken Annular Ring

A broken annular ring occurs when drill tolerances cause the via to deviate from the center during manufacturing, leading to the annular ring breakout.

Annular Ring Tangency

Annular ring tangency refers to a situation where part of the via touches the edge of the pad, typically caused by the drill bit not being aligned with the markings. This can cause the via to deviate from the center and negatively affect the normal operation of the circuit.

What Can Best Technology Do for You?

At Best Technology, we have over 18 years of experience in PCB manufacturing, and we understand the importance of the annular ring in creating reliable and high-quality PCBs. Our team of experts works closely with clients to ensure that every PCB is designed with the right annular ring specifications, minimizing the risk of defects and improving the overall performance of the circuit board. In additional to this, our sales-assistant will send EQ (engineer question) file and WF (working file for manufacturing) to customer for a final approval before starting production.

We use state-of-the-art equipment and precision techniques to manufacture PCBs that meet the highest standards. Whether you’re designing a single-layer PCB or a complex multi-layer board, Best Technology has the expertise and experience to deliver high-quality PCBs that meet your needs. We’re here to support your projects and ensure that your PCBs are reliable, efficient, and built to last.

Let us help you create the perfect PCB with the right annular ring design to ensure seamless electrical connections and superior functionality. Reach out to Best Technology today for your PCB needs!

Tags:annular ring, annular ring meaning, annular ring pcb, annular ring shape
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What is pcb sbu technology? HDI PCB manufacturer

Friday, February 14th, 2025

What is pcb sbu technology? SBU technology in PCB refers to “Sequential Build Up”, which is a technology used to manufacture high-density interconnect (HDI) multi-layer PCBs. It achieves higher wiring density and smaller board size by stacking additional conductive and insulating layers layer by layer on the basis of traditional multi-layer boards and using micro-vias (blind or buried vias) to achieve inter-layer connections.

What is pcb sbu technology?

PCB SBU technology stands for Sequential Build Up technology. It is an advanced process used in the manufacturing of high-density interconnect (HDI) PCBs.

This technique involves building up multiple layers of a PCB in a sequential manner, typically starting from the inner layer and adding layers progressively.

Each layer is added using specialized processes that make it possible to create smaller vias, more complex routing, and finer features compared to traditional PCB manufacturing.

SBU technology is essential in HDI PCB production, which is commonly used in devices that require high performance in a compact form factor, such as smartphones, medical devices, automotive electronics, and other modern electronic systems.

By using SBU technology, multiple layers can be stacked with precision while maintaining the electrical performance and signal integrity required by these applications.

What is HDI PCB?

An HDI PCB (High-Density Interconnect PCB) is a type of printed circuit board that offers higher density and more compact designs.

HDI PCBs are designed to handle fine-pitch components, high-frequency signals, and miniaturized electronic devices. They use advanced manufacturing techniques such as microvias, blind vias, and buried vias, making them the preferred choice for high-performance applications.

HDI boards are typically characterized by:

Smaller and finer traces – Supporting higher component density.

Microvias – Very small holes used to connect different layers in the PCB.

Blind and buried vias – Vias that only connect specific layers, improving space utilization.

Stacked or staggered via construction – For reducing board size and increasing routing flexibility.

By leveraging HDI technology, manufacturers can create more compact and efficient PCBs that perform exceptionally well in the most demanding electronic applications.

What is a buried hole?

A buried hole is a via that connects two inner layers of a PCB but does not go through the entire thickness of the board. These vias are entirely enclosed within the PCB layers and are not visible on the outer surfaces.

Buried holes are commonly used in HDI designs to enable multi-layer connections while optimizing the space on the outer layers for components and routing.

How Buried Holes Benefit PCB Design:

Maximized board space – Since they don’t take up space on the outer layers.

Reduced signal interference – By isolating inner-layer connections from the external surface.

Improved electrical performance – Essential for high-speed, high-frequency designs.

Buried holes are particularly beneficial in high-performance electronic devices that require dense component placement without compromising the integrity of the signal paths.

What is a blind hole?

A blind hole is a via that connects an outer layer to one or more inner layers of the PCB, but does not extend all the way through the board.

It is “blind” because it doesn’t go all the way through the PCB like a through-hole. These types of vias are often used when connections need to be made between surface components and inner layers without occupying precious outer-layer space.

Benefits of Blind Holes:

Space-saving – No need for holes that go all the way through the board.

Enhanced routing flexibility – Allows for more efficient use of the board’s surface.

Reduced component size – Perfect for designs with high-density components that need a compact form.

Blind vias help ensure that HDI boards can be designed with multiple layers, allowing for more complex circuits without increasing board size. They are ideal for devices with multi-functional, high-density circuit layouts.

What is a microvia?

A microvia is a very small via used in HDI PCB designs to create electrical connections between the layers. Microvias are typically laser-drilled, allowing for precise and tiny holes that are ideal for high-density applications.

They generally have a diameter of less than 150 microns, making them perfect for high-frequency, high-speed circuits that need to minimize space without sacrificing performance.

Key Advantages of Microvias:

Reduced board size – Enables more compact designs without compromising performance.

Improved electrical performance – Allows for shorter signal paths and fewer signal losses.

Better signal integrity – Minimizes the risk of signal interference and distortion.

Enhanced routing flexibility – Provides designers with more options for creating high-density, complex circuits.

Microvias are indispensable for modern PCB designs that demand high performance, miniaturization, and advanced electrical features.

What are the advantages of Sbu technology?

Sequential Build-Up (SBU) technology offers several key advantages, especially in the production of HDI PCBs.

By allowing for the precise construction of multi-layered boards with intricate features, SBU technology helps manufacturers achieve designs that would be impossible with traditional PCB technologies.

Key Benefits of SBU Technology:

Enhanced Performance in Smaller Footprints – By using fine-pitch components, microvias, and blind or buried vias, SBU technology enables the creation of small, highly efficient circuits.

Faster Production Cycle – The sequential build-up process reduces the overall time required to produce multi-layer boards compared to conventional methods.

Cost-Effective for Prototyping – Ideal for low to medium-volume runs, where modifications can be made quickly without the need for large-scale tooling changes.

Better Signal Integrity – The small via sizes and precise routing make SBU technology particularly effective for high-speed, high-frequency designs.

Flexibility in Layer Design – SBU allows for a more flexible design process, offering greater options in terms of layer stack-ups and via types.

Overall, SBU technology empowers PCB designers to achieve advanced, high-performance circuits while maintaining cost-effectiveness and design flexibility.

What is the difference between PCB substrate and laminate?

The terms substrate and laminate are often used interchangeably in the context of PCB manufacturing, but they refer to different parts of the PCB construction process.

Substrate – The substrate is the core material of the PCB. It is typically made of fiberglass (FR4) or ceramic and provides the foundational structure on which the circuit layers are built.

Laminate – A laminate refers to the outer layer material that is bonded to the substrate. It is often a combination of resins and copper foil.

Key Differences:

Substrate is the primary base material, while laminate is used to build up the layers on top of the substrate.

Substrate provides mechanical support, whereas laminate contributes to the board’s electrical properties.

Both are crucial components in the production of HDI PCBs and other advanced circuit boards, ensuring strength, reliability, and functionality.

What is the difference between PCB and package substrate?

The main difference between a PCB substrate and a package substrate lies in their intended function and design:

PCB Substrate – Primarily used for circuit boards, these substrates provide structural support for the PCB’s electrical connections.

Package Substrate – This is used in chip packaging and provides connections between the chip and the external circuit.

The PCB substrate is mainly concerned with signal routing and electrical connections, while the package substrate focuses more on chip integration and interfacing with external systems.

Conclusion:

PCB SBU technology has revolutionized the way high-density interconnect (HDI) PCBs are designed and manufactured.

At Best Technology, we leverage our extensive expertise and advanced manufacturing capabilities to produce top-tier HDI PCBs with SBU technology. For inquiries, contact us at: sales@bestpcbs.com

Tags:HDI PCB, pcb sbu, sbu pcb
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What is PCB? PCB Full Form

Tuesday, December 3rd, 2024

PCB Full Form

PCB stands for Printed Circuit Board. It is a crucial part of nearly all modern electronic devices. It acts as a physical base for electronic components while also providing the pathways to connect them electrically. Without PCBs, electronic devices would rely on cumbersome wiring that is prone to failure. With PCBs, electronics are compact, efficient, and highly reliable.

What Is a PCB?

A PCB (Printed Circuit Board), also known as a printed wiring board, is one of the most essential components in the electronics industry. It is used in almost every electronic device, from small gadgets like digital watches and calculators to large systems such as computers, communication equipment, and military weaponry. Wherever electronic components like integrated circuits are present, PCBs are necessary to electrically connect them.

In the early stages, paper-based copper-clad PCBs were commonly used. However, with the introduction of semiconductor transistors in the 1950s, the demand for PCBs skyrocketed. The rapid development and widespread use of integrated circuits (ICs) further increased the need for smaller and more densely packed circuit boards. This has driven continuous advancements in PCB technology.

What Is a PCB Made Of?

PCBs consist of multiple layers, each serving a distinct purpose. Here’s a breakdown of the common layers:

1. Substrate

The substrate is the core material that provides mechanical strength to the PCB. The most common material is FR4, a fiberglass-reinforced epoxy resin. It provides mechanical support and offers good heat resistance. For flexible PCBs, materials like polyimide are used, allowing the board to bend without breaking.

‌2. Copper Layer

This is a thin sheet of copper laminated onto the substrate. It forms the conductive pathways that carry electrical signals. Depending on the PCB’s design, there may be one or more copper layers. Single-layer boards have copper on one side, while multilayer boards have copper on multiple layers.

3. Solder Mask

Solder mask is a layer of polymer coated on copper foil to protect unused copper tracks. It prevents oxidation and helps prevent solder bridges during assembly. It also adds an aesthetic touch to the PCB. It is usually green, hence the name “green oil”. While green is the most common color, solder masks can be blue, red, black, white or even transparent.

4. Silkscreen

Screen printing is a layer of paint, applied to a solder resistance film. The silkscreen layer contains printed information, such as component labels, polarity markings, and company logos. It helps technicians and engineers identify components and troubleshoot the board. The silkscreen is usually white but can be in other colors.

‌5. Through-holes and via holes‌

Through holes are used to mount components and vias to connect the layers of the board together for electrical interconnection and thermal management.

‌6. Component

Electronic components, such as resistors, capacitors and integrated circuits (IC), mounted on the PCB, secured in place using soldering.

Types of PCB

PCB can be classified according to the number of circuit layers and hardness of the board.

1. According to the number of layers, a PCB can be divided into single sided PCB, double

sided PCB and multi-layer PCB. The common multi-layer board is generally 4-layer or 6-layer, and the complex multi-layer board can reach dozens of layers. PCB board has the following three main types of division:

Single-sided PCB

This type has copper tracks on only one side of the board. It is the simplest and most cost-effective type of PCB. Single-sided PCBs are used in low-complexity devices like calculators, LED lighting, and simple power supplies.

Double-Sided PCB

In double-sided PCBs, copper tracks are present on both sides of the board. They allow for more complex circuits compared to single-sided boards. They are commonly used in power supplies, audio systems, and industrial equipment.

Multilayer PCB

Multilayer PCBs consist of three or more layers of copper and insulating material stacked together. They are ideal for complex circuits requiring high density and performance. Applications include computers, smartphones, and aerospace systems.

2. According to the hardness, a PCB can be divided into rigid PCB, flexible PCB and rigid-

flex PCB. Generally, the PCB shown in the left side below is rigid PCB, and the right side is flexible PCB (or short for FPC). The main difference between a rigid PCB and a flexible PCB is that a flexible PCB can be bent.

The common thickness of rigid PCB is 0.2mm, 0.4mm, 0.6mm, 0.8mm, 1.0mm, 1.2mm, 1.6mm, 2.0mm and so on. The common thickness of flexible PCB is 0.2mm. Since it has thinner thickness, the place where the parts are to be soldered will add a thick layer behind it (generally PI, FR4, stainless stiffeners), and the thickness of the thick layer is 0.2mm and 0.4mm. Common rigid PCB materials include: phenolic paper laminate, epoxy paper laminate, polyester glass felt laminate, epoxy glass cloth laminate. Flexible PCB materials commonly include: polyester film, polyimide (PI) film, fluorinated ethylene propylene film.

What Is the Difference Between PCB and PCBA?

Many people confuse PCB with PCBA, but they are not the same.

A PCB is the bare board with copper traces and no components attached. It provides the framework for electronic connections.
A PCBA (Printed Circuit Board Assembly) is a PCB with all components soldered and assembled onto it. It is a fully functional electronic circuit ready for integration into a device. In short, PCBA is the finished product, while PCB is the base.

In simple terms, a PCB is the blank canvas, while a PCBA is the finished painting.

What File Type Is Used for PCB?

When designing a PCB, specific file types are needed for manufacturing. The most commonly used file is the Gerber file. It contains all the information required to fabricate the PCB, including:

Copper layer data: Specifies the layout of copper traces.
Solder mask data: Indicates where the solder mask should be applied.
Silkscreen data: Provides details for component labels and markings.
Drill files: Indicate the size and location of holes.

Additional files used in PCB manufacturing include:

Netlist files: Define the electrical connections between components.
BOM (Bill of Materials): Lists all components required for assembly.
Pick-and-Place files: Provide coordinates for placing components during assembly.

How Do You Know if Your PCB Is Damaged?

Detecting a damaged PCB early can prevent device failure. Here are some common signs of a damaged PCB.

Physical Damage: Cracks, burns, or broken traces are visible on the board.
Overheating: Discoloration or burnt areas indicate overheating issues.
No Power: The device fails to power on, which could point to a short circuit or broken trace.
Malfunctioning Components: Components behave erratically or fail to function.
Unusual Odor: A burning smell may indicate a serious short circuit.

How to Fix a PCB Board?

Repairing a PCB depends on the nature and extent of the damage. Here are some common repair techniques:

1. Visual Inspection

Examine the PCB for visible damage, such as cracks, broken traces, or burnt components. Use a magnifying glass for a closer look.

2. Soldering Repairs

Resolder loose or broken connections using a soldering iron. Ensure the solder joints are clean and secure.

3. Trace Repair

For broken traces, use a conductive pen or solder a thin copper wire to bridge the gap.

4. Component Replacement

Identify and replace faulty components like resistors, capacitors, or ICs. Ensure the replacement components match the original specifications.

5. Testing

After repairs, use a multimeter to check for continuity and verify that the circuit functions correctly.

In some cases, especially with extensive damage, it may be more practical to replace the PCB rather than repair it.

Where Is PCB Used?

PCBs are used in nearly every industry, powering devices and systems that drive modern life. Some common applications include:

1. Consumer electronics – smartphones, tablets, laptops, televisions, and gaming consoles.

2. Automotive – engine control units, infotainment systems, sensors, and lighting.

3. Medical devices – diagnostic equipment, monitoring systems, pacemakers, and imaging devices like MRI machines.

4. Aerospace – navigation systems, communication devices, and flight control systems.

5. Industrial equipment – automation systems, machinery control, power supplies, and sensors used in industrial environments.

FAQs about PCB

1. Why Is a PCB Important in Electronics?

PCBs offer a reliable and efficient way to connect electronic components, enabling compact and functional devices.

2. Can a PCB Be Recycled?

Yes, PCBs can be recycled to recover valuable metals like copper, gold, and silver, reducing electronic waste.

3. How Long Does a PCB Last?

The lifespan of a PCB is around 50-70years, but it depends on its quality and usage conditions. High-quality PCBs can last for decades with proper care.

4. What Are Common PCB Defects?

Common defects include open circuits, short circuits, and misaligned layers, which can affect performance.

5. How Do You Test a PCB?

Testing methods include Automated Optical Inspection (AOI), In-Circuit Testing (ICT), and functional testing.

Choosing a reliable PCB manufacturer ensures you receive high-quality boards tailored to your needs. A trusted supplier like Best Technology can provide durable, efficient, and custom-designed PCBs that meet your project requirements, ensuring long-term success.

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What are PCB Designs Called?

Friday, November 29th, 2024

If you’re working with electronics, you’ve probably heard of Printed Circuit Boards (PCBs). They’re at the heart of almost every electronic device we use today. But have you ever wondered what are PCB designs called? Are they just called PCB designs, or is there more to it? Well, it turns out there are quite a few terms for PCB designs, and each one refers to a specific aspect of the design process. Let’s take a closer look at these terms, how they’re used, and what makes each one unique.

What Are PCB Designs Called?

PCB designs are often referred to by different names depending on the context or the stage of the design process. Let’s explore the most common terms:

1. PCB Layout

This is probably the most frequently used term. When someone mentions a PCB layout, they’re talking about the physical arrangement of components and the routing of electrical connections (also called traces) on the board.

Think of it like designing the floor plan of a house. The layout ensures that everything fits within the available space and that all the rooms (or in this case, components) are connected in the right way.

2. Circuit Board Design

Sometimes, you’ll hear people refer to the process as circuit board design. This term emphasizes the broader design aspect, from planning the circuit to placing components and routing connections. It’s a more general term that covers everything from the initial schematic to the final layout.

3. PCB Schematic

While the schematic is technically just one part of the design process, some people refer to the entire design as the schematic. This is more common among those who focus on the circuit’s logic rather than its physical structure.

4. Gerber Files

Once the design is complete, it’s converted into a set of files called Gerber files. These files contain all the information needed to manufacture the PCB. Sometimes, people use the term Gerber files to refer to the finished design, even though it’s technically just the output.

5. EDA (Electronic Design Automation) File

In professional environments, PCB designs are often called EDA files. These are the files created by design software like Altium Designer, KiCad, or Eagle. They contain all the details of the design, including the schematic, layout, and design rules.

What Is the Difference Between a PCB Design and a Schematic Design?

Many people use the terms PCB design and schematic design interchangeably, but they serve different purposes in the design process.

Schematic Design

Represents the electrical connections between components.
Focuses on the logic and functionality of the circuit.
Uses symbols to represent components like resistors, capacitors, and transistors.
Helps engineers understand how the circuit works.

PCB Design

Translates the schematic into a physical layout.
Focuses on the placement of components and routing of traces.
Considers factors like board size, layer count, and thermal performance.
Ensures the circuit can be manufactured and assembled.

In summary, the schematic shows what the circuit does, while the PCB design shows how it does it physically.

PCB Schematics Elements

A schematic is the starting point for any PCB design. It provides a clear visual representation of the circuit’s functionality. Here are the key elements of a schematic:

1. Component Symbols

Each component in the circuit is represented by a symbol. For example, a resistor is usually shown as a zigzag line, while a capacitor is two parallel lines.

2. Nets (Connections)

Lines connecting the symbols represent electrical connections, known as nets. These nets define how components interact with each other.

3. Reference Designators

Lines connecting the symbols represent electrical connections, known as nets. These nets define how components interact with each other.

4. Values and Ratings

The schematic also shows the values and ratings of components, such as the resistance of a resistor or the capacitance of a capacitor.

5. Power and Ground Symbols

Every circuit needs power and ground connections. These are represented by standard symbols, ensuring the circuit has a common reference point for voltage.

Common Terms in PCB Design

1. Silkscreen Layer

The silkscreen layer contains text, logos, and symbols printed on the surface of the PCB to help identify components and guide assembly. It can also include part numbers, component values, and polarity markings.

2. Via

A via is a hole in the PCB that allows electrical connections between different layers. Vias are often used in multi-layer PCBs to route signals between the top and bottom layers or inner layers.

3. Copper Pour

A copper pour is a large, solid region of copper that is poured over areas like ground or power planes. It helps reduce noise, increase current-carrying capacity, and improve thermal dissipation.

4. Trace Width

Trace width refers to the thickness of the copper traces used to connect components. The width of a trace must be designed to carry the required amount of current without overheating.

5. Drill Hole

A drill hole is a hole that is made in the PCB to accommodate components with leads or for vias. The size and placement of drill holes are critical to the assembly process.

6. Solder Mask

The solder mask is a protective layer applied over the PCB to prevent solder from bridging between pads. It also helps prevent oxidation of the copper traces and improves the board’s overall durability.

7. Pad

Pads are small copper areas on the PCB where components are mounted or soldered. Pads can be through-hole or surface-mount, depending on the type of component.

8. Bill of Materials (BOM)

The BOM is a comprehensive list of all the components required for the assembly of a PCB. It includes details like part numbers, quantities, and specifications for each component.

9. Impedance Control

Impedance control is the process of ensuring that the impedance of the PCB traces matches the requirements of the signals that will travel through them. This is important for high-speed and RF circuits.

10. Stack-up

Stack-up refers to the arrangement of layers in a multi-layer PCB. It defines how the copper, dielectric, and other materials are stacked to create the board.

11. Daisy-Chaining

Daisy-chaining is a method of connecting multiple components or pins in a series, often used in signal or power distribution systems within the PCB design.

12. Overcurrent Protection

Overcurrent protection refers to circuits designed to prevent excessive current from flowing through the PCB traces, often by using fuses or resistors that limit the current flow.

13. Design for Manufacturability (DFM)

DFM refers to designing the PCB in a way that makes it easier and more cost-effective to manufacture. This includes factors like trace width, pad size, and component placement.

14. Routing

Routing is the process of designing the electrical paths that connect the components on a PCB. Proper routing ensures that signals are carried efficiently with minimal interference.

15. Thermal Via

Thermal vias are specially designed vias used to transfer heat away from high-heat components to other parts of the PCB or a heat sink.

16. Electromagnetic Interference (EMI) Shielding

EMI shielding involves using design techniques, such as grounding and the use of shielding components, to protect sensitive parts of the PCB from electromagnetic interference.

17. Differential Pair

A differential pair is a set of two traces that carry complementary signals, often used in high-speed designs like USB or Ethernet to minimize noise and improve signal integrity.

18. Power Distribution Network (PDN)

The PDN refers to the system of traces and planes that deliver power to various components on the PCB. Proper PDN design is crucial to ensure reliable power delivery and minimize voltage drops.

19. Electrical Rule Check (ERC)

ERC is a process that checks the schematic design for electrical issues like unconnected nets, incorrect component connections, or incorrect power supply connections.

20. Multi-layer PCB

A multi-layer PCB contains more than two layers of conductive material and is used for more complex designs that require high-density circuits, especially in smaller devices.

21. Surface-Mount Technology (SMT)

SMT is a method for mounting components directly onto the surface of the PCB, rather than inserting them through holes. This allows for smaller, more compact designs.

22. Through-Hole Technology

Through-hole technology involves inserting component leads through holes in the PCB and soldering them on the opposite side. It’s commonly used for components that require strong mechanical bonds.

23. Hot Air Soldering

A method of soldering components onto the PCB using hot air, often used in reflow soldering processes for surface-mount components.

24. Trace Routing

Trace routing is the process of laying out the paths that the electrical signals will take through the PCB. Good trace routing ensures efficient and reliable signal transmission.

25. Tenting

Tenting refers to the process of covering the vias with a layer of solder mask, leaving the pad open. It helps prevent solder from flowing into vias during soldering.

PCB Design vs. PCB Layout

Although often used interchangeably, PCB design and PCB layout have different meanings:

PCB Design: Refers to the entire process, from schematic creation to generating manufacturing files.

PCB Layout: Specifically focuses on the physical arrangement of components and routing of traces on the board.

In simple terms, PCB layout is a part of the overall PCB design process.

PCB Design Process

Designing a PCB is a multi-step process that requires careful planning and attention to detail.

1. Schematic Capture

The process starts with creating a schematic diagram that defines the circuit’s functionality and connections.

2. Component Selection

Next, components are selected based on the circuit requirements. Factors like size, power rating, and cost are considered.

3. PCB Layout

Components are placed on the board, and traces are routed to connect them. This step requires balancing electrical performance with physical constraints.

4. Design Rules Check (DRC)

The layout is checked for errors or violations of design rules to ensure it meets manufacturing standards.

5. Gerber File Generation

Once the design is complete, Gerber files are generated. These files are used by manufacturers to produce the PCB.

6. Fabrication and Assembly

The PCB is fabricated, and components are assembled to create the final product.

FAQs

Q: What software is used for PCB design?

A: Popular software includes Altium Designer, Eagle, KiCad, and OrCAD.

Q: How many layers can a PCB have?

A: PCBs can have anywhere from one to 16 or more layers, depending on complexity.

Q: Why is trace width important?

A: Trace width affects the current-carrying capacity and signal integrity of the circuit.

Q: What is a multilayer PCB?

A: A multilayer PCB has multiple layers of copper separated by insulating material, allowing for more complex designs.

Q: How long does it take to design a PCB?

A: The time varies based on complexity. Simple designs may take a few days, while complex designs can take weeks.

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Via in Pad Design Guideline & FAQs

Tuesday, November 26th, 2024

What is Via in Pad?

With the improvement of the integration of electronic products, the package of components is getting smaller and smaller, and the pin spacing is also getting smaller and smaller. In complex PCB design, the signal cannot be fanned out without punching the disc hole, and the signal must be drawn from the next layer through the disc hole. Especially in the miniaturization applications of ‌BGA (Ball Grid Array) and ‌SMD (Surface Mount Device) chips, the process of disc holes has been widely used.

Via in pad is a design methodology in PCB manufacturing where vias are directly embedded in the pads of surface-mount devices (SMDs). Traditional vias are placed near the components with traces connecting them to the pads. However, in via-in-pad designs, the vias and pads are combined, which saves space and shortens trace lengths. This approach is particularly useful in HDI PCBs, where board real estate is limited, and signal integrity is critical.

What is Via-in-Pad Plating?

Via-in-pad plating refers to a specialized manufacturing process where vias embedded in pads are filled and plated over to form a smooth, conductive surface. This process involves:

Via Filling: The via hole is filled with a material, often epoxy or a conductive paste, to eliminate voids and provide structural stability.
Copper Plating: The filled via is then plated with copper to create a uniform and conductive layer.
Surface Finish: A finish such as ENIG (Electroless Nickel Immersion Gold) or HASL (Hot Air Solder Leveling) is applied to ensure solderability.

Proper via-in-pad plating prevents solder wicking, a phenomenon where solder flows into the via during reflow, causing insufficient solder on the component leads.

Is Via-in-Pad Expensive?

Via-in-pad designs are undeniably more expensive than traditional vias. The additional manufacturing steps, such as via filling, plating, and the need for precise alignment, contribute to the higher costs. Moreover, the advanced equipment and materials required for this process add to the overall expense.

However, for designs that demand high performance, such as smartphones, medical devices, and aerospace electronics, the benefits of via in pad often outweigh the cost. It allows for compact layouts, improved performance, and better thermal management, making it indispensable for cutting-edge applications.

What Size is a Via-in-Pad?

The size of a via-in-pad is influenced by the PCB’s application, layer count, and the size of the components used. In HDI PCBs, via sizes typically range from 0.15 mm to 0.4 mm in diameter. Microvias, often used in via-in-pad designs, can be as small as 0.1 mm.

The diameter must align with the pad size to avoid compromising the pad’s mechanical and electrical integrity. Designers also need to consider the PCB manufacturer’s capabilities when selecting via sizes, as extremely small vias may require advanced fabrication techniques.

What are the Drawbacks of Via in Pad?

While via in pad offers several advantages, it also comes with notable challenges:

Higher cost
Soldering defects
Complex manufacturing
Thermal stress risks
Complex manufacturing process

Can You Put Vias Under Components?

Yes, placing vias under components is common in advanced PCB designs, particularly with via in pad. This technique is often used for BGAs, QFNs, and other fine-pitch components.

However, proper design and manufacturing practices must be followed to prevent defects. Filling and plating the vias ensure they do not interfere with soldering. Additionally, simulations and testing are essential to validate the design and ensure reliability.

Traditional Vias vs. Via-in-Pad Design

Traditional vias are placed outside the component pad, with traces connecting them to the pads. While this approach is cost-effective, it consumes more space and may result in longer trace lengths, increasing parasitic effects.

Via-in-pad designs embed the vias directly within the component pads, reducing trace lengths and optimizing space. They enhance signal integrity, thermal performance, and overall board aesthetics but at a higher cost and complexity.

When to Use Via-in-Pad Design?

Via-in-pad designs are not always necessary, but they are indispensable in specific scenarios where performance, space optimization, and thermal management are critical. Below are the situations where via-in-pad designs are most appropriate:

1. High-Density Interconnect (HDI) PCBs

When designing HDI PCBs with compact layouts and high layer counts, via-in-pad is essential. This design technique optimizes the limited space available, allowing for more components and connections on the board. It is particularly useful for devices like smartphones, wearables, and IoT devices where miniaturization is key.

2. Fine-Pitch Components

Via-in-pad designs are commonly used for components with fine pitches, such as:

BGA chips: BGAs have numerous pins closely spaced, leaving minimal room for traditional routing. Via in pad provides a clean solution to connect signals directly.
QFNs: QFNs require vias under the pads for effective routing and thermal management.

3. High-Speed and RF Applications

In high-speed and RF circuits, signal integrity is paramount. Via-in-pad designs minimize trace lengths, reducing parasitic inductance and impedance mismatches. This makes them ideal for applications like:

5G communication systems
High-frequency radar systems
Advanced networking equipment

4. Improved Thermal Management Needs

For power components or heat-sensitive devices, via in pad aids in efficient thermal dissipation. By directly connecting the pads to thermal vias leading to internal or external layers, heat is transferred away from the components. This is critical for:

High-power LEDs
Voltage regulators
Power amplifiers

5. Limited PCB Real Estate

In designs with severe space constraints, via in pad maximizes usable board area. This allows for additional routing space and supports high component density without sacrificing performance. Applications like medical implants and aerospace electronics greatly benefit from this approach.

6. Double-Sided Component Placement

When components are placed on both sides of the PCB, traditional vias can interfere with the routing on the opposite side. Via in pad eliminates this issue by embedding the vias within the pads, simplifying double-sided designs.

7. High-Performance Computing Systems

For processors, GPUs, and other high-speed ICs, via in pad ensures reliable power delivery and signal integrity. It is frequently used in:

Data centers
High-performance workstations
AI hardware

Guidelines for Via-in-Pad Design

Via-in-pad designs require meticulous attention to detail to ensure reliability and performance.

1. Decide on the most suitable via type based on your design requirements:

Microvias: Ideal for high-density designs due to their small size.
Blind/Buried Vias: Useful for connecting internal layers without penetrating through the entire board.
Through-Hole Vias: Less common in via-in-pad but may be necessary for specific designs.

2. Fill the vias with appropriate materials to ensure mechanical stability and prevent solder wicking:

Non-Conductive Epoxy Fill: Provides a reliable, flat surface for soldering.
Conductive Fill: Used when electrical connectivity through the via is needed.

3. The plating over the filled vias should be smooth and flat to avoid soldering issues. Use a high-quality copper plating process to enhance electrical and thermal conductivity.

4. Collaborate with your PCB manufacturer early in the design process to align on their capabilities. This includes:

Minimum via diameter and pad size.
Spacing requirements between vias and traces.
Maximum number of vias that can be placed in pads.

5. Ensure the via size is proportionate to the pad size. A via that is too large can compromise the pad’s structural and electrical integrity, while a too-small via may not provide the necessary connectivity or thermal performance.

6. For high-power applications, incorporate thermal relief patterns or thermal vias.

7. Maintain sufficient spacing between vias and other components or traces to prevent electrical interference or thermal stress.

8. To avoid solder flowing into the via during reflow soldering:

Use filled and capped vias.
Employ surface finishes like ENIG (Electroless Nickel Immersion Gold) or OSP (Organic Solderability Preservative) for enhanced soldering reliability.

9. When using via in pad for power components or ground connections, thermal relief patterns help prevent excessive heat buildup. These are especially important in high-current designs.

Need assistance in designing via-in-pads in your PCB design? Leave your comments on below, our design experts will help to solve them.

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What is the HDI PCB core thickness?

Wednesday, October 23rd, 2024

The core thickness range of HDI PCB (High Density Interconnect Circuit Board) mainly depends on its design and application requirements. According to different processes and application scenarios, the core thickness of HDI PCB can vary from 0.6mm to 1.0mm.

What is the standard thickness of a PCB core?

The standard thickness of PCB core boards usually includes the following specifications: 0.5mm, 0.7mm, 0.8mm, 1.0mm, 1.2mm, 1.5mm, 1.6mm, 2.0mm, 2.4mm, 3.2mm, 6.4mm. These thickness specifications are widely used in different electronic products and circuit board designs.

The thickness of PCB includes not only the thickness of the core board, but also the total thickness of all layers such as copper layer, solder mask layer and silk screen. The standard thickness ranges widely, from thinner 0.5mm to thicker 6.4mm, suitable for different application requirements.

Choosing the right PCB thickness is essential to ensure the performance and reliability of the circuit board. Thicker PCBs have higher mechanical strength and load-bearing capacity, and are suitable for products with high power and large electronic components, such as industrial, automotive, aerospace and military applications.

Ultra-thin PCBs are suitable for small electronic products such as smartphones, smart wearable devices and laptops due to their lightweight characteristics.

What is the thickness tolerance of a PCB core?

The thickness tolerance of a PCB core varies according to different thickness ranges.

For PCBs with a thickness of less than or equal to 1mm, the board thickness tolerance is ±10% of the board thickness. For example, a PCB with a thickness of 0.5mm has a tolerance of ±0.05mm; a PCB with a thickness of 0.8mm has a tolerance of ±0.08mm.

For PCBs with a thickness greater than 1mm and less than or equal to 1.6mm, the tolerance is ±0.14mm.

For PCBs with a thickness greater than 1.6mm and less than or equal to 2.0mm, the tolerance is ±0.18mm.

For PCBs with a thickness greater than 2.0mm and less than or equal to 2.4mm, the tolerance is ±0.22mm.

For PCBs with a thickness greater than 2.4mm and less than or equal to 3.0mm, the tolerance is ±0.25mm.

For PCBs with a thickness greater than 3.0mm, the tolerance is ±10%.

These tolerance standards apply to most PCB manufacturing processes, ensuring the stability and reliability of the PCB.

What is the difference between HDI and non-HDI PCB?

The main differences between HDI PCB and non-HDI PCB are their line density, size, production process and electrical performance. HDI PCB (High Density Interconnect PCB) has higher line density, smaller size and better electrical performance, while ordinary PCBs are lacking in these aspects.

First of all, the design and structure of HDI PCB are significantly different from ordinary PCBs. HDI PCB adopts higher line density and more complex circuit layout, which enables smaller size and lighter design. In contrast, ordinary PCBs have lower line density and are suitable for some application scenarios that do not require high line density.

In terms of production process, the manufacturing process of HDI PCB is relatively complex, including laser drilling, stacked copper plates, etching technology, etc., to achieve high-density interconnection and complex circuit wiring. The manufacturing process of ordinary PCB is relatively simple, generally using photolithography, etching process, etc.

In terms of electrical performance, HDI PCB uses technologies such as blind holes and buried holes to reduce signal transmission paths and improve the transmission rate and stability of electrical signals. In addition, HDI PCB also has better radio frequency interference, electromagnetic wave interference, electrostatic discharge and thermal conductivity performance.

Finally, the cost of HDI PCB is relatively high, mainly due to its complex manufacturing process and high technical requirements. The manufacturing cost of ordinary PCB is low, which is suitable for some application scenarios with low requirements for line density and technology.

How thick is a 2 layer PCB core?

The thickness of a 2-layer PCB core is usually 0.4mm.

PCB core is a base material composed of copper foil, solid resin material and glass fiber, with a certain hardness and thickness. Common PCB core thickness specifications include 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 1.0mm, 1.2mm, 1.5mm, 1.6mm, 2.0mm, 2.4mm, etc.

Among the common specifications of Shengyi core boards, the thickness of 0.4mm is widely used. In addition, the performance of multi-layer PCBs does not directly depend on the number of layers, but more reflects the space requirements during design.

Are HDI PCB reliable?

HDI PCBs are reliable. HDI PCBs are manufactured using high-density and high-reliability interconnection technology, with higher line density and more complex circuit layout, which can achieve smaller and lighter electronic devices.

Compared with ordinary PCBs, HDI PCBs perform well in anti-interference ability and electromagnetic compatibility, and can effectively reduce the impact of external interference on signal transmission, while having higher reliability and longer service life.

The reliability of HDI PCBs is due to the high-quality substrates, solder mask and copper foil materials used, as well as strict manufacturing processes and quality control. These characteristics enable HDI PCBs to maintain stable performance and quality in various harsh environments.

In addition, the development trend of HDI PCBs is towards higher integration, higher signal transmission rate, better electromagnetic compatibility and optimized thermal management capabilities, which further enhances its application value in high-performance and high-density integration requirements.

What are the benefits of HDI PCB?

The main benefits of HDI PCB include high-density wiring, high-performance signal transmission, adaptability to high-frequency applications, miniaturization, and thinness. These characteristics make HDI PCB play a vital role in electronic devices, especially in high-end electronic products such as smartphones, tablets, and high-end computers.

First, HDI PCB has the characteristics of high-density wiring, which can achieve more circuit connections in a smaller space. This allows the design of electronic products to be more compact and meet application scenarios with extremely high space requirements.

Secondly, HDI PCB excels in high-performance signal transmission, can provide better signal transmission quality and electrical performance, and is particularly suitable for processing high-speed and high-frequency signals.

In addition, HDI PCB also has the advantages of miniaturization and thinness, which contributes to the thinness and miniaturization of electronic products, making the equipment more portable while maintaining high performance.

These benefits of HDI PCB are due to its advanced manufacturing process and technology. By adopting finer line widths and smaller apertures, HDI PCB achieves higher wiring density and signal transmission speed.

At the same time, by optimizing material selection and circuit design, HDI PCB can reduce the loss and reflection during signal transmission and improve the integrity and accuracy of the signal. In addition, HDI PCB also has better anti-interference ability and electromagnetic compatibility, which can effectively reduce the impact of external interference on signal transmission.

The application range of HDI PCB is very wide, including smart phones, tablets, laptops, medical equipment and communication equipment. Due to its high-density interconnection and excellent electrical performance, HDI PCB plays an important role in these fields, promoting the development of the PCB industry, so that more dense components can be arranged more closely on HDI boards.

What are the disadvantages of HDI PCB?

The main disadvantages of HDI PCB include high cost, complex production process, environmental sensitivity and possible quality problems.

First, the cost of HDI PCB is relatively high. This is because high-precision manufacturing technology and special materials are required in its manufacturing process, which all lead to its cost increase.

In addition, HDI PCB is usually used in high-performance equipment, and the value of these equipment itself is also high, which further pushes up the price of HDI PCB.

Second, the production process of HDI PCB is very complicated. Due to its high density of lines and components, the manufacturing of HDI PCB requires highly precise processes and equipment. This not only increases the difficulty of production, but may also lead to a longer production cycle, further increasing costs.

In addition, HDI PCB has certain requirements for the environment. Due to its delicate structure, HDI PCB is very sensitive to humidity and temperature changes in the environment. Improper storage or transportation conditions may cause the PCB to become damp or deformed, affecting its performance and reliability.

Finally, HDI PCB may have some quality problems. Due to the complexity of the production process, HDI PCB may have problems such as poor solderability, delamination, short circuit, open circuit, etc. These problems may need to be avoided through strict quality control and testing.

The core thickness of HDI PCB is an important parameter, which is directly related to the performance and application of PCB. When choosing the core thickness of HDI PCB, factors such as application requirements, design requirements and manufacturing process need to be considered comprehensively to select the appropriate core thickness.

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Can you use AC in PCB?

Monday, October 7th, 2024

Can you use AC in PCB?AC can be used in PCB boards. PCB boards are designed to support the use of AC, and the functions of AC can be realized through proper circuit design and component selection.

Can you use AC in PCB?

The use of AC in PCB boards requires consideration of the characteristics of AC. The current magnitude and direction of AC change continuously over time, which requires the components and layout on the PCB to adapt to such changes. For example, components such as inductors and capacitors play an important role in AC circuits, and their parameters and layout need to be carefully designed to achieve the desired circuit performance.

Specifically, AC circuit design on PCB boards includes selecting appropriate components, layout, and routing. For example, using test instruments such as LCR digital bridges can measure the parameters of components in AC circuits to ensure that the performance of the circuit meets the design requirements. In addition, reasonable ground routing and layout can reduce signal interference and ensure the stable transmission of AC.

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.

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What is high density interconnect?

Friday, October 4th, 2024

High density interconnect (HDI) technology plays a pivotal role in the electronics field, and high-density interconnect boards are the core embodiment of this technology. As a key connection carrier between electronic components, it is an important guarantee for realizing miniaturization, high performance and multi-functionality of electronic equipment.

What are high density interconnects?

High-density interconnect (HDI) is a printed circuit board (PCB) manufactured using higher-density wiring technology. Compared with traditional PCB, HDI board achieves miniaturization, lightweight and higher wiring density of circuit board through smaller aperture, finer line width/spacing and more layers of blind and buried hole technology to adapt to Electronic devices, especially mobile devices, require efficient space utilization and high-performance transmission.

The core of HDI technology lies in its high-density wiring design. By increasing the number of PCB layers, reducing wire width and spacing, and using micro-hole (such as laser drilling) processes, HDI technology significantly increases circuit complexity and wiring density. This technology is often used in electronic products such as smartphones, tablets, and smart wearable devices, meeting the needs of these devices for efficient space utilization and high-performance transmission.

What is the difference between PCB and HDI?

The main differences between PCB and HDI boards lie in wiring density, manufacturing process, size and cost. HDI boards use high-density interconnection technology, with higher wiring density and more complex circuit layouts, while ordinary PCBs are relatively simple and suitable for some application scenarios that do not require high line density.

There are significant differences between HDI boards and ordinary PCBs in terms of wiring density, manufacturing process, size and cost. HDI boards use high-density interconnection technology, with higher wiring density and more complex circuit designs, enabling smaller size and lighter design requirements. In comparison, the wiring density of ordinary PCB is low, which is suitable for some application scenarios that do not require high line density.

In terms of manufacturing process, HDI boards use more advanced manufacturing processes, including laser drilling, stacked copper plates and etching technology, to achieve high-density interconnection and complex circuit wiring. In comparison, the manufacturing process of ordinary PCBs is relatively simple, usually using photolithography and etching processes.

Because HDI boards have higher circuit density and complex circuit layouts, their size and thickness are usually smaller, making them suitable for applications that require compact packaging and space constraints. Ordinary PCBs do not have these restrictions and are suitable for more diverse application scenarios.

In terms of cost, since the manufacturing process of HDI boards is more complex and has higher technical requirements, its manufacturing cost is relatively high. In comparison, ordinary PCBs have lower manufacturing costs and are suitable for some application scenarios that do not have high circuit density and technical requirements.

What is the structure of HDI PCB?

The structure of HDI PCB mainly includes inner laminate, outer laminate, gaskets, blind and buried vias and other components. ‌

The inner laminate is the core part of the HDI circuit board. It is composed of multiple layers of conductive materials and insulating materials alternately stacked. It mainly realizes the transmission and control of circuit signals. The number of layers of the inner laminate can be very high. It uses microporous technology to achieve a high-density circuit layout and has excellent electrical performance and stability‌.

The outer laminate is located on the outside of the inner laminate and is also composed of multiple layers of conductive materials and insulating materials alternately stacked. Its main function is to protect the internal circuit from the influence of the external environment, such as humidity, temperature, mechanical stress, etc. The outer laminate can also provide additional grounding and shielding to improve circuit performance and reliability‌.

The gasket is an insulating material used to connect the inner laminate and the outer laminate. Its main function is to isolate the inner and outer laminates, prevent electrical interference, and provide certain mechanical support to ensure the stability of the circuit board.

A blind buried via is a non-penetrating through hole located inside the inner laminate. It is not directly connected to the outer laminate and mainly realizes the electrical connection between the inner laminates. Blind and buried vias do not penetrate the entire circuit board, which can effectively reduce the thickness and weight of the circuit board and improve the circuit board’s thermal resistance and mechanical stress resistance.

What are the advantages of HDI PCB?

The main advantages of HDI PCB include high-density interconnection, optimized wiring design, good signal transmission performance, high reliability and stability, smaller size and weight, and higher production efficiency. ‌

First, HDI PCB achieves higher line density by using higher-level packaging technology and smaller apertures. This means that under the same board size, HDI PCB can accommodate more electronic components and complex circuit designs, thereby improving the performance of the product. ‌

Second, the design of HDI PCB is more compact. Through multi-layer wiring and micro-via technology, the size and weight of the circuit board can be greatly reduced, adapting to the trend of modern electronic devices to pursue thinness and shortness.

Finally, the production process of HDI PCB is more efficient, and advanced technologies such as laser opening, thin film transformer, and cover packaging are used to achieve high-efficiency production.

What are the disadvantages of HDI PCB?

1. Difficulty in impedance control: The complexity of pattern transfer and electroplating processes increases production difficulty, which may lead to unstable impedance values.

2. Complex production cost control: The high-density circuit part of HDI PCB has a slow etching speed, which leads to excessive etching of isolation lines and increases production costs.

‌3. Environmental impact‌: During the electroplating and etching process, a large amount of copper ions enter the waste liquid, causing environmental pollution and difficulty in recycling.

4. High difficulty in design and manufacturing: HDI PCB is manufactured using micro-blind buried via technology and built-up method. The technical requirements are high and the process is complex, which increases the difficulty of design and manufacturing.

‌5. High material costs‌: The materials used in HDI PCB, such as PI and other high-performance materials, are more expensive, increasing manufacturing costs‌.

6. Quality issues: HDI PCB is prone to problems such as poor solderability and delamination during the manufacturing process. These problems may require higher process capabilities and quality control to avoid.

What are the applications of HDI PCB?

HDI PCB (High Density Interconnect PCB) can greatly reduce the size and weight without sacrificing performance by using microvias and tiny line widths and spacing, and is particularly suitable for portable electronic devices.

The main application areas of HDI PCB include:

‌Communication field‌: HDI PCB can achieve higher data transmission rates and lower energy consumption by increasing the number of tiny components.

‌Automotive Electronics‌: HDI PCB reduces product volume and production costs in the high integration of automotive electronic products, ensuring the stable operation of automotive electronic products.

‌Medical Equipment‌: HDI PCB is widely used in high-precision and high-stability medical equipment, improving the accuracy, sensitivity and stability of the equipment‌.

‌Mobile Communication‌: HDI PCB supports high-speed data transmission, maintains stable signal transmission, and supports a variety of wireless communication technologies‌.

‌High Performance Computing (HPC)‌: HDI PCB provides efficient interconnection channels, significantly improving computing performance and response speed‌.

In short, high-density interconnection circuit boards, as an important embodiment of high-density interconnection technology, play an irreplaceable role in the development of modern electronic technology. With the continuous advancement of technology, its future development prospects are still very broad, and it will continue to promote the development of electronic devices in the direction of smaller, stronger, and smarter.

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Board electronics with holes

Friday, October 4th, 2024

Board electronics with holes The types of vias in PCB include through holes, blind holes and buried holes, which have different characteristics and requirements in design and manufacturing. The selection of the appropriate via type should consider the number of PCB layers, wiring density, signal frequency, cost budget and production process. The via design should pay attention to avoid affecting the welding quality, preventing electrical short circuits, and saving costs in high-density packaging.

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.

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