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What Is the Importance of Ground Plane in PCB EMC Design?

Saturday, March 30th, 2024

In the design of electronic products, electromagnetic compatibility (EMC) is a crucial consideration. Particularly in the design of printed circuit boards (PCBs), the rationality of EMC design directly impacts the performance and stability of the product. Among the many factors affecting EMC, one factor is especially critical, and that is the design of the ground plane. Today, let’s talk about the impact of grounding on EMC.

In an electronic product, grounding is a very important element, it is directly related to EMC compliance. Especially in large equipment, the grounding of multiple systems and subsystems is involved. It can be said, a good grounding system means the half successfully of a product.

What are Ground Plane and EMC in a PCB?

The ground plane, as the reference potential in a circuit, not only carries the return path of current but also plays a role in electromagnetic shielding and noise suppression. In high-frequency circuits, the impedance and layout of the ground plane have a significant impact on signal integrity. Unreasonable ground plane design may result in signal interference, increased radiation, and decreased system stability.

EMC stands for Electromagnetic Compatibility. It refers to the ability of electronic devices and systems to operate properly in their intended electromagnetic environment without causing or experiencing interference. EMC ensures that devices can function without adversely affecting other devices nearby or being affected by electromagnetic interference from external sources. Generally, the ground planes will showing three shapes, please see as following:

Why A Grounding Must be Designed in PCB?

Grounding can be understood as an equipotential point or plane serving as the reference potential for a circuit or system, which can be a specific ground layer in a PCB or the metal chassis of a product. While many perceive the purpose of designing a ground plane primarily to prevent external electromagnetic interference (EMI), but in printed circuit board design, it serves multiple purposes beyond this.

Generally, a well-designed ground provides a common reference zero potential for all circuit units within a system, ensuring no potential difference between circuits and thus stable operation. It also protects circuits from damage, ensuring the safe functioning of electronic products. For instance, ground can provide discharge paths for transient disturbances and dissipate accumulated charges on product metal enclosures induced by static electricity, to prevent potential sparks that may cause interference internally. Additionally, choosing appropriate grounding for shielding structures can yield effective electromagnetic shielding.

Grounding design is very necessary especially for medical industry. As we know, there are many medical devices are directly connected to patients’ bodies, such as monitors. In cases where the chassis carries voltage due to poor grounding, fatal risks may arise. Furthermore, grounding reduces common-mode interference currents flowing through PCBs and prevents high-frequency EMI signals within products from reaching equivalent radiating antennas. Thus, grounding is typically a primary method for noise suppression and interference prevention.

Design Principles of Ground Plane in PCB

A well-designed grounding system should not only consider the radiation and conduction of individual PCBs but also prevent from a systemic perspective. In the design phase, failure to carefully consider the grounding system may indicate a high likelihood of EMC failure for the system. So, knowing the design principles is extremely important to make sure the successful of EMC.

  • Keep it short and wide

To reduce the impedance of circuits, especially in high-frequency circuits, the ground plane should be made as short and wide as possible. This helps to minimize the return path of the current, thereby reducing EMI.

  • Partition layout

For complex PCB designs like multilayer PCBs, it is recommended to use a partition layout to separate the ground planes of different functional modules. This helps to isolate noise interference between different modules.

  • Single-point ground and multipoint ground

Depending on the circuit’s operating frequency and signal characteristics, choose between single-point grounding or multipoint grounding. Single-point grounding is suitable for low-frequency circuits, while multipoint grounding is more suitable for high-frequency circuits.

PCB_ground_plane_design
  • Ground plane

Where possible, use a ground plane as the ground. The ground plane can provide a low-impedance return path and aid in electromagnetic shielding.

How to Optimize Your Grounding Design?

As for PCB that has already design the circuit layout, how to optimize the ground to get the maximum EMI? Here are some tips that may helpful for you.

  • Fill the blank areas of the PCB with ground planes to increase the ground plane’s area and reduce impedance.
  • Reducing the area of ground loops helps to decrease electromagnetic radiation and induced noise.
  • Power lines and ground planes should be placed as close as possible and run parallel to reduce the area of the current loop.
  • Placing decoupling capacitors between power and ground planes helps to filter out high-frequency noise.
Semi_flexible_pcb

In PCB EMC design, ground plane design is an essential step that cannot be ignored. By following the principles and optimization methods of ground plane design, the EMC and signal integrity of electronic products can be significantly improved. Therefore, in PCB design, sufficient attention and consideration must be given to ground plane design. Welcome to contact Best Technology if you want to know more about ground and EMC design.

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Top 6 Considerations You Must Know About PCB Designs

Wednesday, March 27th, 2024

Electronics devices and parts are existing everywhere in this big data era, and more and more engineers trying to step in the electronics design and development. As a one-stop PCB and PCBA manufacturer in China, Best Technology would like to share some basic considerations and tips during the PCB designs. Hope this can help you.

Substrate Material

Substrate is the main composition of a circuit board and it mainly used for suppler and copper foil insulation. The commonly materials are FR4 and PI. FR4 is a widely acceptable international grade for fiberglass reinforced epoxy laminated, and it always used for making rigid PCB or rigid-flex PCB. FR4 substrate has good insulation and mechanical strength, so it can be widely used in various applications. However, PI has higher heat and chemistry resistance, more suitable for high temperature and chemical corrosion environment.  

Circuit Layout

The layout design depends on the dimensions, performance and reliability of a circuit board, it is needed to follow your supplier’s standard to make sure the fast production time and high quality.

  • Min line width

Please make sure your line width within your supplier’s manufacturing capability, that is to say, if it is less than the minimum line width will not able to be produced. The best way is if the design conditions available, the larger the line width, the better the factory production. Generally, the line width keeps around 10mil is the best. In another word, if your line width is less than normal standard, it would be difficult for you to find a suitable supplier.

  • Min line spacing

Min line spacing means the distance between trace and trace. Normally, from the production aspect, the distance from line to pads should not less than min line spacing, and it would be better if it is larger, generally equal to or more than 10mil.

  • The spacing between circuit to outline should be control in 20mil.

Plug-in Hole

The diameter of plug-in hole should be considered by the side of components, but it is necessary that it must greater than the component’s pins, it is recommended that greater at least 0.2mm. That is to say, if the pin of components is 0.6mm, then the plug-in holes should be greater than 0.8mm. Otherwise, the plug-in components would be probably difficult to insert into PCB because of the tolerance control during the manufacturing and assembly

Min Hole Diameter

As we all know, the holes in PCB almost be used for mounting components, connect circuit and provide the electrical connection between layers. So how to design the hole also is crucial during the designing. Generally, the min hole diameter depends on the drill bitter that vendor used, always around 0.2-0.4mm. You can ask your supplier during the design evaluation.

Copper Thickness

Copper foil is a layer of metal foil on the PCB board that is used to conduct current. The thickness of copper foil is usually in oz (ounces), such as 1oz, 2oz, 3oz, etc. The thickness of the copper foil will affect the conductivity and heat dissipation performance of the PCB board.

Impendence Control

Impedance control is a key parameter in high-speed signal transmission and high-frequency circuit design. It involves board thickness, copper foil thickness, substrate dielectric constant, pad and line layout and other factors to improve the signal integrity and anti-interference ability of the PCB board.

The production process of PCBs is rather complex, involving a wide range of techniques from simple mechanical processing to sophisticated machining, so you should understand the design rules very clearly when you are trying to design a PCB board. Its applications are also diverse, from consumer electronics to industrial machinery, where PCBs are utilized.

Best Technology offers one-stop PCB solutions, we offer service from prototyping to large-scale production and assembly. With experienced engineers and service teams, we ensure successful fulfillment of your requirements. Just send us with your design files, and we will make the circuit board for you in a very short time.

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Do You Know What Is PCB Stiffener Busbar?

Wednesday, March 27th, 2024

Busbar PCB is an electronic component, also known as a socket board or mother board, which is an important part of an electronic device and is used to connect and transmit current and signals, so it plays a crucial role in the design of electronic devices. Busbar PCB is like a PCB coated with an “ear”, which we also call it as stiffener busbar. Want to know more about it? Welcome to reading on!

(Busbar_pcb)

What is PCB Stiffener Busbar?

A busbar circuit board is a key component used in electrical systems. It usually consists of a main conductive busbar (usually copper or aluminum) that is covered with an insulating material such as prepreg or resin. Busbar boards are used to transmit high currents in power systems, such as in industrial equipment, power distribution systems, and control panels.

These boards typically have multiple slots for inserting electrical connectors or electrical devices. The design of the bus board can be customized according to the specific application requirements to adapt to different current and voltage requirements. They are widely used in the industrial and commercial sectors because they provide reliable power transmission and connectivity solutions.

(Busbar_aluminum_pcb)

What Are Benefits of Using a Busbar PCB?

Busbar stiffener pcb serves as a crucial element of conducting electricity, especially when simplifying the power distribution process, saving costs and requiring greater flexibility. They come in a variety of sizes and different coatings, such as aluminum and copper. The material type, dimension, size and shape of the busbar determine the current capacity it can carry. Compared with a coil harness, though it is expensive in manufacturing, but has longer life and does not need to replace in a short time. Here we listing some benefits of busbar PCB:

  • Efficient Power Distribution

With the fast development of new energy cars and vehicles, the electronic parts in the cars also should updated to meet the demands of renewable energy powers. So the busbar PCB stands out because it can distribute the powers in devices efficiently. Meanwhile, it also can help to reducing the consumption of energy. Because of its integrated nature, it can easily adapt to the integration of renewable energy, which is quite intriguing to consider in this advanced era of energy.

  • High Conductivity

The busbar stiffener on a PCB is typically crafted from either copper or aluminum. Copper, renowned for its excellent conductivity, stands out as the preferred material for busbars due to its capacity to facilitate the flow of electrons. Moreover, copper’s robust nature enables it to withstand harsh environmental conditions and high temperatures, thus bolstering its longevity and durability. But if you want PCB that can carry higher conductivity, ceramic PCB is the best choice but a little bit higher cost.

(Busbar_copper_pcb)
  • Can be Customized

Busbar is a highly customization product in PCB design, it offers various options for its mechanical capability. So maybe you can find it in every industry, such as educations, medical instruments, factories, communications and various electronic devices. Tight space and compact devices require substitute electrical distribution, and busbars serve the purpose right. Due to its high compact and strong mechanical and chemistry, busbar PCB can be used in extremely harsh weather. This makes them a good choice in substations or devices that need to used outdoors.

  • Space Saving

Due to the copper materials mounted on the PCB, Busbar PCBs can replace multiple traces with a single, wider conductive strip, saving valuable space on the board. This compact design is particularly useful in applications where space is limited. In addition, busbar PCB provides multi-layer structure when your design is complex and has density traces network.

By means our extensive PCB & PCBA manufacturing and professional engineering team, we are highly able to build and design busbar PCBs according to your specific requirements. Meanwhile, we follow the strict quality system to make sure the high-quality of products. You are welcome to contact us or send e-mail if you want to make such busbar stiffener PCB.

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Top 1 Design and Manufacturing Considerations for Bendable Aluminum PCBs

Thursday, March 7th, 2024

You know, bendable aluminum PCBs have gained prominence in various electronic applications due to their unique ability to flex and conform to curved surfaces. Unlike traditional rigid PCBs that are commonly composed of materials like fiberglass , these PCBs utilize aluminum as the base material, allowing it bendable and flexibility when needed. Compared to the rigid characteristics of traditional metal core PCB, bending aluminum PCB can be adapted to specific space requirements and shape requirements. In this article, we will introduce the characteristics of bendable aluminum PCBs and explore the key considerations that engineers and manufacturers need to pay attention during the design and production process.

What Are the Benefits of Bendable Aluminum PCBs?

May some designers are reraly to know the bendable aluminum PCB, in their congnition, the bendable PCBs are including flex circuits, rigid flexible circuit and FFC, and aluminum PCB is classfied into one of rigid PCB. But here, Best Technology is so proud to say, we have developed bendable aluminum PCB and we can manufacture it with fast delivery and high-quality, this is what we prouded.

The primary advantage of bendable aluminum PCBs is their flexibility. They can be bent and shaped to fit into various form factors and designs, making them suitable for applications where space is limited or where flexibility is required and traditional rigid boards are not ideal. Common applications include wearable devices, curved displays, and other electronic systems with unconventional form factors.

Additionally, bendable aluminum PCB has the advantages of aluminum, so it has good heat dissipation and higher thermal management than traditional PCBs. This feature is crucial for maintaining the reliability and performance of electronic devices, especially those operating in high-temperature environments.

Considerations During the Design Process

Al Material Selection:

Considering that it is a bendable aluminum substrate, it must be satisfied that the material selection should be bendable but at the same time have good heat dissipation of the metal base. This aluminum base material is a specially designed aluminum alloy or aluminum base composite material. Meanwhile, the thickness of the material is critical, such as the material is generally from 0.2mm to 1.6mm, of which 0.2mm to 1.0mm is the more common bending metal substrate thickness.

Flexibility Requirements:

Defining the flexibility requirements is a crucial step in the design process. The degree of bending, bending radius, and any other factors related to flexibility must be clearly defined based on the intended application. For instance, a wearable fitness tracker might require a specific bending profile to comfortably conform to the curvature of the wrist.

Also note that the bending radius is different for materials of different thicknesses. In general, a smaller bending radius usually corresponds to a thinner board material, while a larger bending radius can accommodate a thicker board material.

Circuit Layout:

The layout of the circuit components plays a pivotal role in ensuring the longevity of bendable aluminum PCBs. Designers should strategically plan the arrangement of components to accommodate bending without subjecting critical elements, such as sensors or microcontrollers, to excessive stress. Even distribution of components contributes to a balanced bending profile.

And the pad should not be designed at the bend of the bending, which will cause damage to the assembly components after bending, or even no way to bend. In addition, the welding pad near the bending cross should also be kept away from the bending line to avoid collision and extrusion of the components after bending.

Bending Radius:

Determining the minimum bending radius that the PCB can tolerate is essential for preventing structural damage or compromise in electrical performance. Specific bending radii should be defined based on the application’s needs. For example, a bendable aluminum PCB designed for a wearable device might need to withstand repeated bending with a predefined radius.

Dielectric Layer:

Choosing an appropriate dielectric material is crucial for maintaining insulation between different layers of the PCB. The dielectric layer should possess flexibility to withstand bending without compromising its insulating properties.

As we know, when design the aluminum PCB, the thermal conductivity is also important. Bendable aluminum also has the thermal conductivity requirement, but when the thermal conductivity material is higher, the higher the content of ceramic powder in material. And when the content of ceramic powder is higher, the brittleness of the material is higher, and it is easier to break or break after bending. The material of 1W/m.k is more bendable than 3W/m.k。

(Bendable_MCPCB)

Considerations During the Manufacturing Process

Bendable aera line:

For the production requirements of the light plate, the V-cut mark is generally used to determine the complete line at the bend, and attention should be paid to the depth control of the v-cut, so as not to damage the line.

Testing and Validation:

Prototyping is a vital phase in the manufacturing process of bendable aluminum PCBs. Thorough testing and validation are necessary to ensure that the PCB meets the required electrical and mechanical specifications. Bending tests simulating the intended application conditions should be performed to assess the PCB’s durability. such as bending test, bending angle test.

Generally speaking, after the bare board finished, it’s not bendable to the required angle. In order to avoid bad transportation or collision, some customers require not to bend and they will bend it by themselves. But if the customers don’t want to bend the board by himself, we also can help to bend it, it will require mold and it need to custom the package for shipping. The custom package can help to protect the damage in shipping.

Collaboration with Manufacturers:

Close collaboration with experienced PCB manufacturers is key to successful production. Manufacturers with expertise in flexible PCB fabrication can provide valuable insights into the manufacturing process. Working together ensures that the design aligns with manufacturing capabilities, optimizing the production of bendable aluminum PCBs.

Conclusion

In a word, the design and manufacturing of bendable aluminum PCBs involve a series of critical considerations to ensure the success and reliability of the final product. From material selection and flexibility requirements to testing, validation, and compliance with industry standards, each step plays a pivotal role in creating PCBs that meet the unique demands of modern electronic applications. By carefully addressing these considerations, designers and manufacturers can unlock the full potential of bendable aluminum PCBs in diverse and innovative electronic devices. Welcome to contact Best Technology if you want to know more.

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What Is Immersion Silver? Why Choose It for PCB Coating?

Monday, February 26th, 2024

Due to the growing concerns and advocacy for environmental friendliness, as well as the prohibition of harmful substances like lead (tin), an increasing number of industries are moving away from the use of HASL (Hot Air Solder Leveling) technologies for PCB (Printed Circuit Board) surface treatment. The current trend is to use other surface treatments such as OSP, gold plating, immersion tin, immersion silver, ENIG and ENEPIG. Among them, immersion silver becoming a popular choice since it has excellent performance and cost effectiveness.

What is Immersion Silver Finish?

Immersion silver finishing is an environment friendly surface treatment that coating a layer of silver (about 0.1~0.4um) on the copper surface to ensure the good solderability when assembly. When comparing its functional performance with other surface finishes like OSP and ENIG, immersion silver falls between them. It exhibits outstanding solderability and exceptional solder joint strength, surpassing OSP, which lacks a conductive barrier. However, when employed as a contact surface, immersion silver demonstrates lower strength compared to gold.

What is the Working Principle of Immersion Silver?

Immersion silver finishing uses chemical deposition to finish the whole processes. Electrochemical deposition is a method of reducing and depositing metals onto the surface of an object by controlling the current in a solution. In the immersion silver process, the pad serves as the anode (positive electrode), while silver acts as the cathode (negative electrode), with a current applied between them. This causes silver ions (Ag+) to be reduced to silver metal under the influence of the electric field, subsequently adhering to the pad surface and gradually forming a silver layer.

The displacement reaction of immersion silver is:

2Ag+ + Cu = 2Ag + Cu++

This method utilizes both electrical current and chemical reactions to deposit silver from the solution onto the surface of the PCB pad, creating a uniform and porous silver layer.

Silver Plated Analyzing: Pros vs Cons

Before selecting the immersion silver coating, we should understand its advantages and disadvantages to consider whether it is suitable for your PCB project and end-applications.

Pros of immersion silver:

  1. Cost-effective than immersion gold
  2. Good surface flatness and low contact resistance
  3. Corrosion resistance
  4. Good solderability, especially for BGA chips or smaller components
  5. Environment friendly
  6. High reliability

Cons of immersion silver:

  1. Difficult to handle, must wear gloves
  2. Special storage conditions – if the package is opened and not all PCBs need to be used, it must be resealed quickly or use them within 24h.
  3. Peelable masks can’t to use

Important Points You Must Know About Storage

  1. For storage and handling, it needs more careful than immersion tin and OSP.
  2. It is compliant with ROHS and safer than HASL.
  3. In the dry conditions, it can be stored 6-12months.
  4. PCB with immersion silver must be soldered within 24hours if package is unsealed.
  5. If the immersion silver PCB has been stored for more than 12 months, a solderability testing is must before assembling.

Immersion Silver vs ENIG

ENIG also is a common surface treatment in the PCB manufacturing, its full name is Electroless Nickel/Immersion Gold finishing. The ENIG technology is a relative expensive than immersion silver, and it suitable for more complex layout design.

ENIG plating involves safeguarding the copper pads on PCBs by first applying a layer of nickel and then overlaying the copper surface with a thin layer of gold. In essence, the procedure is akin to immersion silver, but it significantly improves PCBs by providing enhanced resistance to oxidation, superior solderability, and excellent surface planarity.

Let’s review the performance comparison between these two surface treatments:

Welcome to contact us if you have any questions about immersion silver or other surface treatment.

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How Does the Ceramic PCB Works in IGBT Modules?

Friday, January 19th, 2024

IGBT (Insulated Gate Bipolar Transistor) is a bipolar junction transistor (BJT) with a MOS gate, or we can say that an IGBT module is a combination of BJT and MOS module. Despite its small size, the IGBT chip can control the transmission of electrical energy. It can switch the current 100,000 times within 1 second under an ultra-high voltage of 650 million volts.

What is the Working Principle of IGBT?

IGBT combines the features of a transistor and a switching circuit, making it a new type of electronic component that can control current efficiency. Its structure allows it to achieve current control from turn on to off without generating excessive leakage current, as well as not affecting the operation of other circuits.

The working principle of IGBT modules including two parts – the current control of MOS gate and BJT transistor. When the voltage of MOS gate changes, it affects the conduction of the transistor, thus controlling the flow of current. When the BJT comes into play, it controls the flow of current, so that improve the working efficiency of the IGBT.

(Working_principle_of_IGBT)

How Does A Ceramic PCB Protect IGBT Modules from Overheat?

As you know, IGBT modules have been applied for many years in various industries such as automotive, industrial, aerospace, consumer electronics, and more. However, optimizing the thermal dissipation of IGBT packaging is crucial to enable the modules to operate at higher power conditions. If heat dissipation is improved, IGBT modules can be used in more advanced applications.

You might be wondering how much heat does an IGBT module generate during running? It’s equivalent to the heat produced by 100 electric furnaces. This substantial amount of heat must be dissipated immediately from the IGBT chip, that’s why the ceramic circuit board stands out.

(Ceramic_pcb_with_DPC_technology)

In IGBT modules, ceramic PCBs are placed beneath the IGBT chip, or we can say the chip is assembled on the ceramic circuit board. The ceramic PCB connects and supports the chip, rapidly dissipating heat to the outer package. This method protects the chip from the adverse effects of heat.

Why ceramic PCBs Are Suitable for IGBT thermal dissipation?

Ceramic materials exhibit excellent thermal dissipation and electrical insulation properties. Unlike aluminum metal core PCBs, ceramic PCBs do not use insulation layers that hinder heat dissipation. In the manufacturing process of ceramic PCBs, copper foil is directly bonded to the ceramic substrate under high pressure and temperature (it depends on the different technology and different copper thickness). During PCB manufacturing, IGBT and other components are mounted on the circuit board through assembly technology.

Ceramic materials have extremely high insulation capabilities, enduring breakdown voltages up to 20KV/mm. At present, there are three ceramic materials that can be used for IGBT modules, they are 99% or 96% Alumina (Al₂O₃), Aluminum Nitride (AlN), and Silicon Nitride (Si₃N₄).

The thermal conductivity of alumina PCB is 15-35W/mK, aluminum nitride PCB is 170-230W/mK, and silicon nitride PCB is 80+W/mK. In contrast, aluminum core circuit boards only have a thermal conductivity of 1-12W/mK.

Applications of Ceramic PCBs in IGBT Packaging

Alumina PCBs are the most commonly used circuit boards in IGBT modules due to their lower cost. But if IGBT modules have higher power or precision requirements, AlN ceramic PCBs and Si3N4 PCBs are the most suitable choices. Because they have higher thermal dissipation and thermal expansion coefficients (CTE) close to semiconductors. Since different ceramic substrate has different features, the uses of ceramic PCB should depend on the specific requirements of IGBT modules.

In addition, with the development of Silicon Carbide (SiC) and Gallium Nitride (GaN) materials, they are starting to be used for IGBT chips due to their high-frequency, high-power, and high-temperature characteristics. Maybe in the future, aluminum nitride PCBs and silicon carbide PCBs will be increasingly applied to high-power IGBT modules in high-density three-dimensional packaging.

Common Properties of Using Ceramic Circuit Board

  • Excellent thermal conductivity and voltage resistance of ceramic substrates.
  • Copper trace layers has extremely high current-carrying capacity.
  • Strong adhesion and reliability between circuit layers and ceramic substrates.
  • Good soldering performance, suitable for wire bonding.
(Ceramic_PCB)

How to Solve the Overheat Issues in IGBT?

Though the ceramic PCB is good at heat dissipation, there still some overheat occasions happened if small power or long-time operation. Here we summarized some solutions for such issues.

1. Clean the heat sink to ensure tight contact between the IGBT and the heat sink.

2. Clean the fan, including the fan blades and lubricate the bearings if needed.

3. Clear the airflow path of the fan.

4. Replace with higher power IGBTs, ensuring the withstand voltage is not lower than the original IGBT’s value.

Above all are the information that we’d shared, welcome to contact us if you want to know more. Best Technology is a historic company which has over 17 years PCB manufacturing experience, here you can enjoy the one-stop ODM & OEM service, one-to-one after sales, quick delivery and high-quality products.

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What Are Differences of ENIG VS ENEPIG in PCB Manufacturing – Series 1

Tuesday, January 2nd, 2024

Surface treatment also called surface finishing, it is a protective layer that through coating a layer of metal organic material on the surface of printing circuit boards (PCBs). Apply a layer of surface treatment enable to protect pads from scratches and oxidation, as well as improve the solderability of components mounting. ENIG and ENEPIG are the two common high-reliable surface finishing types in the circuit board manufacturing, they are not only for FR4-PCB, but also available in ceramic PCB, flex circuits and rigid-flex PCB. Today, Best Team would like to sharing information about ENIG and ENEPIG, and explore the differences between them.

(Assembled_PCB)

How to Select the Right Surface Treatment for Your PCB?

With the rapid development of electronics, there are various of PCB types that can be used in electronic devices, and at the same time, there are also increasingly more surface treatment technics available for selection. Until now, the common surface treatments are OSP, HASL, Immersion Silver, Gold Plating, ENIG and ENEPIG. Each of these surface treatments has its own advantages and disadvantages, so it is necessary to choose the most suitable one for a particular application. The selection of surface finish needs to take into account factors such as cost, application environment, fine-pitch components, the use of leaded or lead-free solder, operating frequency, shelf life, drop and impact resistance, volume and throughput, as well as thermal resistance.

With PCBs trending towards micro-vias and finer traces, and the drawbacks of HASL and OSP, such as flatness and flux elimination issues, becoming more pronounced, the demand for surface treatments like ENIG continues to grow. In addition, black pad is a major weakness of ENIG while ENEPIG enable to solve it very well, making it a preferred choice for those PCBs need to wire bonding.

What is the ENIG Surface Treatment?

ENIG, its full name is Electroless Nickel Immersion Gold, is also known as chemical gold or immersion gold in the electronics industry. This type of surface treatment provides two metal layers—gold and nickel—that manufacturers deposit them on the surface of PCB pads sequentially. This surface finish is a selective surface finish, meaning that certain specific pads may have ENIG surface finish, while others may have different types, such as OSP, HASL, or immersion tin. Here are the main processes of the ENIG coating:

  • Copper activation

In this step, manufacturers will active the copper layer through cleaning process, this way can help to remove the dust and oxides residual on the surface, but also remove any gases or air trapped in the perforations (holes) of the PCB by wetting the surface. Next, micro-etching the PCB surface using substances like hydrogen peroxide or sulfuric acid.

  • Electroless nickel

This process is to coat a layer of nickel on the active copper layer by electroplating. The nickel layer serves as a protective layer or inhibitor, which prevent the copper reactive with other elements.

  • Immersion gold

Immersion gold is the last step of whole ENIG process, immersing the PCB into a mixture, oxidizing the nickel surface, generating nickel ions, and then reducing gold from the mixture. The reduced gold forms a metallic coating to protect the nickel surface. This is the whole process of coating ENIG surface treatment.

(PCB_with_ENIG_surface_treatment)

Advantages of ENIG

  • Surface flatness – good for fine-pitch and small size components like BGA.
  • Suitable for press-fit components since it provides a reliable connection for electrical testing.
  • Suitable for wire bonding and gold-fingers connectors.
  • Cost-effective compared with ENEPIG

Disadvantages of ENIG

  • Black pad issues.
  • Varied coating thickness because of the uncontrolled nickel plated and immersion gold.
  • Poor wettability during PCB assembly.

All in all, ENIG is a good option if you want to mount fine-pitch components on the PCB surface or if you are considering its use in plug-and-pull devices such as WIFI interfaces. In our next blog, we will introduce ENEPIG surface treatment, including its pros & cons and the differences between ENIG and ENEPIG. Pay attention to our news or contact us directly if you want to know more.

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What Is the Role of Electronic Parts on the Circuit Boards?

Tuesday, December 19th, 2023

A circuit board is an independent part of modern electronic devices, equipped with various components that play different roles and functions on the board such as connecting, signal transmission, power distribution, and signal conversion. Theoretically speaking, electronic components are the fundamental units in the devices, and printed circuit board (PCB) serves as a carrier for mounting components, connecting them to completing the functions of electronic systems. Here, we will introduce some common circuit board components and their functions.

(A_PCB_with_components)

What Are Electronic Components?

Electronic components are fundamental building blocks used in the construction of electronic circuits and systems. These components manipulate electrical signals to perform specific functions in electronic devices. Based on their purpose and functionality, electronic components can be categorized into two major types: passive components and active components.

Passive electronic components mainly include resistors, capacitors, inductors, power filters, and so on. They do not have active operational functions such as amplification or signal control. Instead, passive components can only consume or store electrical energy. In electronic systems, their main roles include signal transmission, distribution, filtering, isolation, and other similar functions.

Active electronic components, on the other hand, include transistors, field-effect transistors (FETs), integrated circuits (ICs). Unlike passive components, active components have the ability to actively amplify, control, and manipulate signals related to current, voltage, frequency, and more. They play a crucial role in electronic systems, enabling active operations and functionalities.

(Components_on_a_pcb)

What Is the Functionality of Common Components on PCB?

On an assembled circuit board (PCBA), we can see various of components on its surface. Different components play its unique role and have different function. Here we will introduce the function of common components.

  • Resistor

A resistor is a component used to restrict the flow of electric current. Its purpose is to control the magnitude of current by adjusting its resistance value, ensuring appropriate current adjustment within the circuit.

  • Capacitor

The capacitor has the ability to store charge and release it when needed. Its function is to smooth power supply voltage, stabilize current, and in some cases, perform signal filtering to accomplish signal conditioning. Resistors and capacitors are two common types of electronic components.

  • Diode

Diode is a type of component with unidirectional conductivity. The uses of diode enable to allow current to flow in one direction while blocking reverse current. It is commonly used in power supplies, rectifiers, and other circuits.

  • Transistor

A transistor functions in amplification and switching in a printed circuit board. Its role is to amplify electronic signals, control the flow of current, and it is widely used in circuits such as amplifiers and logic gates.

  • Integrated Circuit (IC)

Integrated circuit is a very important components in those small size circuits, because it can integrate multiple functional circuits onto a single chip. That means it can save space if your design has limited space, enhance system performance and reliability of devices. Integrated circuits find widespread applications in areas such as computers, communication systems, and embedded systems.

  • Inductor

The working principle of inductor is similar to a capacitor, but the different is an inductor has the ability to store and release energy while capacitor is to store and release charge. Its main function is to accomplish energy conversion and distribution in a circuit. Inductors are commonly used in circuits for filtering, power supplies, and more.

  • Variable Resistor

A variable resistor allows for the adjustment of resistance and it always used for modifying circuit characteristics by changing the resistance value. Variable resistors are commonly used in circuits for functions like volume control, light intensity adjustment and some other devices that need to adjust the resistance.

  • Light Emitting Diode (LED)

LED chips is a component that we can see everywhere need to light up. It converts electrical energy into light energy. Its function includes emitting light for indicators, illumination, and it is widely used in circuits such as display screens and indicator lights.

  • Power Module

Power module is always designed to provide the electrical energy required by a circuit. Using power to stabilize output voltage and current, protecting the circuit from external power fluctuations.

  •  Sensor

A sensor can perceive physical quantities or signals in the surrounding environment and convert them into electrical signals. Its function is to enable interaction between the circuit and the external environment. Sensors find wide applications in areas such as automatic control, the Internet of Things (IoT), and more.

(PCBA)

In summary, the various components on a circuit board have their specific roles, work in conjunction with each other, and collectively achieve the functionality and objectives of the circuit. Understanding the functions of these components allows for a better grasp of the working principles of circuit boards, providing reference and guidance for the design and maintenance of electronic products.

However, for some reasons, inspect the components before PCB assembly is the main method that ensures the reliability of a PCBA. In our next post, we will share how to make the incoming inspection for electronic components, leave your messages if you are interested in it.

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What is a E-Tester & how E-tester test PCB?

Saturday, December 2nd, 2023

We often receive this question from customer” what is a E-Tester?” and” how to do E-Test for FR4 PCB?” Hereby I would like to share with you how to use E-Tester to test PCB.

Best Technology in FR4 PCB circuit manufacturing filed since year 2006, we have more than 17 years experiences in PCB fabrication process. We can provide from the design to turn key service for our customer.

Let us come to today’s topic, now what is a E-Tester?

What is a E-tester?

E-Tester is tooling for test PCB during volume production. E-Tester was used to detect the electrical performance of PCB. It is the essential process to test the PCB by this tester before shipment.

As you may know that during PCB process flow, it might be caused some defects by external factors and this is unavoidable.

So, in order to reduce the loss before PCB goes to the next stage when it is assembled with components, Therefore, the E-Test plays important role in PCB quality control to segregate PCBs with defects from shipment to customers and that’s why most of customers require their PCB manufactures to do 100% E test before shipment.

(E_testers)

The E tester mainly checks the open/short circuit for FR4 PCB.

How to do E-test?

Firstly, set up the E-tester on the testing machine and up test datasheet on the computer. Put the board to the E-tester to test the open/short circuit for board and dielectric strength.

Shorts Test: Check to make sure that NO current flows between separate nets by measuring the amount resistance between them.

Opens Test: Check to make sure there is current flow from one “node” to the next for every net on the board.

(Tester_testing)

During the testing, test whether there is short circuit between different network routes of PCB; test whether the PCB network is open to each PAD, and whether the hole is open; Finally, Insulation strength test and the Impedance test.

If the trace open is found on the bare board, the failure location could be repaired or the bare board has to be scrapped. On the other hand, the cost will be increased when PCB goes to the next stage when it is assembled with components, mainly are the sorting cost, component cost and the assembly cost. The compensation ratio is 10 times or even more than the PCB cost and this damages PCB manufacturer’s profit. The worse case is when PCBA is installed onto the end product, the loss caused by defected PCB could be very painful, say up to thousand times of PCB cost. Therefore, the E-Test plays important role in PCB industry to segregate PCBs with defects from shipment to customers and that’s why most of customers require their PCB suppliers to do 100% E test before shipment.

If you want to know more about testing for FR4 PCB board, welcome to visited www.bestpcbs.com or email us, we are very happy to answer your question.

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What is PCB Embedded Component Process?

Wednesday, November 22nd, 2023

The resistance and capacitance buried in multi layers PCB process is a process of burying resistors and capacitors inside the PCB board. Usually, the resistors and capacitors on the PCB are directly soldered on the board through mounting technology, while the buried resistor and capacitor process is to embed the resistors and capacitors into the internal layer of the PCB board.

This kind of printed circuit board consists of a first dielectric layer, a buried resistor, a circuit layer and a second dielectric layer in order from bottom to top. Among them, the part of the buried resistor without a circuit layer on the buried resistor is covered with a polymer isolation layer, and the surface of the polymer isolation layer is roughened, the surface roughness Rz is bigger than 0.01 μm, and the thickness of the polymer isolation layer at the corners is at least 0.1 μm.

The printed circuit board of the utility model covers a layer of polymer isolation layer on the surface of the buried resistor, thereby protecting the buried resistor from being attacked and corroded by chemical chemicals during subsequent wet processes such as browning and super-coarseness, and improving the efficiency of manufacturing buried resistors. Resistor plate process capabilities further promote the application of buried resistive plates to inner layer buried resistors.

The advantages of the buried resistor and buried capacitor process include:

1. Space saving:

Since the resistors and capacitors are embedded directly into the internal layers of the board, space on the PCB board can be saved, making the entire circuit board more compact.

2. Reduce circuit noise:

Embedding resistors and capacitors into the internal layers of the board can reduce the electromagnetic interference and noise of the circuit and improve the stability and anti-interference capabilities of the circuit.

3. Improve signal integrity:

The buried resistance and buried capacitance process can reduce the transmission delay and reflection loss of circuit signals and improve the integrity and reliability of signal transmission.

4. Reduce the thickness of the PCB:

However, the buried resistor and buried capacitor process is relatively complicated in terms of manufacturing and repair, because the resistors and capacitors cannot be directly observed and replaced. In addition, the buried resistance and buried capacitance process is usually used in high-end electronic products, and the cost is relatively high.

When it comes to high-density circuit design, PCB buried resistance and buried capacitance technology has become a very useful technology. In traditional PCB layout, resistors and capacitors are usually soldered on the PCB surface in the form of patches. However, this layout method causes the PCB board to take up more space and may cause noise and interference on the surface.

The buried resistance and buried capacitance process solves the above problems by embedding resistors and capacitors directly into the internal layer of the PCB board.

The following are the detailed steps of the PCB buried resistor and buried capacitor process:

1. Make the inner layer:

When making a PCB board, in addition to the conventional layers (such as outer layer and inner layer), it is also necessary to make a separate inner layer specifically for buried resistance and buried capacitance. These internal layers will contain areas for buried resistors and capacitors. The inner layers are usually made using the same techniques as regular PCB manufacturing, such as electroplating, etching, etc.

2. Resistor/capacitor footprint:

Resistors and capacitors are packaged in a special package in the buried resistor and capacitor process so that they can be embedded into the internal layer of the PCB. These packages are usually thinned to accommodate the thickness of the PCB board and have good thermal conductivity.

3. Buried resistor/capacitor:

In the process of making the inner layer, the buried resistor and capacitor process is completed by embedding resistors and capacitors into the inner layer of the PCB board. This can be achieved through a variety of methods, such as using special pressing techniques to embed resistors and capacitors between inner layers of material, or using laser technology to etch holes in the inner layer material and then fill them with resistors and capacitors.

4. Connection layer:

After completing the inner layer of the buried resistor and buried capacitor, connect it to other regular layers (such as the outer layer). This can be achieved through conventional PCB manufacturing techniques such as lamination, drilling, etc.

In general, the buried resistance and buried capacitance process is a highly integrated technology that embeds resistors and capacitors in the internal layer of the PCB board. It can save space, reduce noise, improve signal integrity, and make PCB boards thinner and lighter. However, due to the complexity, the buried resistor and buried capacitor process is usually used in high-end electronic products with higher performance requirements.

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