Posts Tagged ‘pcb design’

What is Pour Board? What is Copper Pour in PCB?

Monday, September 9th, 2024

What is Copper Pour in PCB Design?

Copper pour, also known as copper coating, refers to filled solid copper on PCB where without trace layout area or idle space. Instead of leaving unused areas bare, copper is poured over them, connecting it to the ground or other designated signals. The main purpose of this process is to reduce the ground impedance, improve the anti-interference ability, reduce the voltage drop. Thereby improving the power supply efficiency, and connect with the ground wire to reduce the loop area. By covering large sections of the board with copper, it also minimizes signal interference and adds a layer of protection to the PCB. Copper pour are essential for designers to maintain signal integrity and reduce unwanted noise.

What is Pour Board? What is Copper Pour in PCB?

The process of copper coating is not only very important for digital circuits, because it can effectively reduce the ground impedance, which is particularly important for digital circuits with a large number of spiking pulse currents. However, for analog circuits, the ground wire loop formed by laying copper may cause electromagnetic coupling interference.

Why Use Copper Pours on Circuit Boards?

Copper pours offer several advantages that make them an essential part of circuit board design. When creating PCBs, some engineers tend to leave many copper-free areas on the board. But a high percentage of copper-free areas on the PCB can negatively affect the product, making it vulnerable to early damage, when copper pouring comes in handy.

There are some novices who think that less copper pouring means that the cost will be lower and lower, which is wrong. It is true that the plating area is small, which can save copper, but there is no way to guarantee the quality, and the appropriate amount of copper pouring can improve the quality of the product.

When the PCB board is placed in the plating tank and the appropriate current is applied, the PCB will show the physical state after dry film coverage. After passing a current, the circuit lines exposed to the outside of the dry film will be plated with copper from the plating tank. The total area of the part of the circuit exposed outside the dry film will affect the value of the current distribution during the plating process, if the bare copper area is large, the current input is uniform, and the current received is more uniform. Therefore, a large area of copper plane must be laid in the design to prevent this from happening. If the total plating area of copper is too small or the pattern distribution is very uneven, the received current will not be uniform. In this way, when powered on, the greater the current, the thicker the copper plating layer (so designed, if only 1OZ is required, then the finished copper thickness can reach 2OZ).

If the gap between current traces is too small, for example about 3mil to 3.5mil, a “clip film” will form between the traces. In other words, the dry film is caught in the middle of the gap, which causes the subsequent base to start the copper in the middle, which can lead to a short circuit if the etching process is not cleaned. In order to maintain the high quality of PCB manufacturing, independent lines must be avoided as much as possible in PCB design and layout. In addition, it is recommended to use a large amount of copper on the entire PCB, if there is a separate line that cannot be covered with copper, then the continuation between the lines must be as wide as possible.

Advantages of Copper Pour Board

1. For EMC (electromagnetic compatibility) requirements, a large area of ground or power supply needs to be covered with copper, which will play a shielding role. For some special area, such as protective ground, it plays a protective role.

2. From PCB manufacturing perspective, generally in order to ensure an uniform copper plating, or avoid lamination deformation and bending, manufacturers always pour copper for those less trace layout PCB board.

3. For signal integrity PCB, pour copper gives the high-frequency digital signal a complete return path, and reduce the wiring of the DC network. In another way, pour copper can help to heat dissipation.

Disadvantages of Copper Pour

1. If the pins of the components are fully covered with copper, the heat dissipation may be too fast, resulting in difficulties in dismantling and repairing the components. Therefore, sometimes in order to avoid this situation, cross connections are used for components (pin contact and pad contact are shown in “+”).

2. Pouring copper in the area around the antenna is easy to cause weak signal, interfered acquisition signal, and the impedance of copper will affect the performance of the amplifier circuit. So the area around the antenna section is usually not covered with copper.

Copper Pour vs Ground Plane

There’s often confusion between copper pours and ground planes. While both serve similar purposes, they are not the same. A ground plane is a layer dedicated entirely to the ground signal, covering the entire surface of a board layer. It ensures a low-impedance path for electrical signals, minimizing interference.

Copper pours, on the other hand, are not necessarily tied to the ground. Designers can connect copper pours to any net, including power lines or signal traces. The primary goal of a copper pour is to fill in empty spaces, whereas a ground plane is dedicated exclusively to providing a ground connection.

Implementation of PCB Copper Pours

When designing a PCB with copper pours, a few best practices help in optimizing its performance. Here are some useful tips:

Assign Copper Pours to Ground First

When designing, prioritize assigning continuous copper to ground layers over power planes. A solid ground plane improves overall performance, providing a reliable reference for signals and reducing noise. Every PCB should have strong, consistent ground connections.

Monitor Trace Currents

Although reducing inductance is advantageous, flooding the board with copper can sometimes interfere with circuit tuning. Be mindful of traced paths, especially in high-current areas, to maintain proper load control.

Maintain Symmetry in Copper Pours

Ensure copper pours are symmetrical on both sides of the PCB. This balance helps prevent issues like board warping due to uneven expansion or moisture absorption. Symmetrical copper distribution is essential for the board’s structural integrity.

Avoid Acute Angles

Keep copper pours free from long, narrow protrusions or angles sharper than 45 degrees. Such shapes can become weak points, breaking off or acting as antennas during vibration or shock, potentially causing functional failures.

Incorporate Relief Features

Adding slots, anti-pads, and thermal spokes can relieve stress caused by material expansion, especially for large copper pours used on power planes. These features ensure mechanical stability and ease soldering.

Carefully Review Design Masks

Automated copper pour shapes may need manual adjustments to remove artifacts or undesirable patterns around complex components. Always review and fine-tune these masks to achieve optimal results.

When copper pours are correctly connected to appropriate nets, designers can enhance both the electrical and physical properties of the circuit by distributing copper strategically across the board.

Copper Pour Clearances and Settings

When designing a PCB with copper pours, clearances and settings play a crucial role in ensuring proper functionality and avoiding issues like short circuits. Here are PCB copper pour suggestions based on standard PCB board:

1. Trace to Copper Pour Clearance

Standard clearance: 0.2 mm (200 µm) or 8 mils
High-voltage applications: 1 mm (1000 µm) or 40 mils (or more, depending on voltage levels)

2. Pad to Copper Pour Clearance

SMD pads: 0.2 mm to 0.3 mm (8-12 mils)
Through-hole pads: 0.3 mm to 0.5 mm (12-20 mils)

You can adjust these values based on the pad size and the net to which the copper pour is connected.

3. Copper Pour Width and Thickness

The width and thickness of the copper pour should be chosen based on the current-carrying capacity of the board:

Minimum width: 1.5 mm (60 mils) for low-current signals
Power lines: At least 2-3 mm (80-120 mils), depending on current
Copper thickness: 35 µm (1 oz/ft²) is standard, but for higher currents, you can use thicker copper like 70 µm (2 oz/ft²) or more.

4. Via Clearance in Copper Pours

Standard via clearance: 0.2 mm (8 mils)
High-current via clearance: 0.5 mm (20 mils)

Clearance should be adapted to the board’s layer stack-up and current needs.

5. Thermal Relief Spokes

Spoke width: 0.3 mm to 0.5 mm (12-20 mils)
Spoke count: Typically 4 thermal relief spokes per pad
Clearance to pad center: 0.5 mm (20 mils)

6. Copper Pour to Board Edge Clearance

Standard clearance: 0.5 mm (20 mils) from the board edge
High-voltage boards: 1 mm (40 mils) or more

Layer Placement of Copper Pours

Copper pours can be placed on any layer of a PCB. In multi-layer PCBs, copper pours are often added on internal layers to maximize performance. For example, ground and power pours are frequently found on internal layers to reduce noise and improve thermal dissipation.

On outer layers, copper pours serve to enhance thermal management. They distribute heat from high-power components and help maintain an even temperature across the board. It’s important to balance the placement of copper pours with other components to ensure overall board stability and functionality.

Copper Pour PCB Design Considerations

1. The open areas in the design must be minimized and the open Spaces filled with copper.

2. It’s important to assess the current-carrying capacity. Make sure the copper pour is thick enough to handle the expected current loads, especially in power applications.

3. If there is no room for the copper, the two wires, the two pads, and the distance between the wires and the pads are designed to be 2 ounces thick with a minimum spacing of 8 mil.

4. When pouring copper, keep a certain distance from the ordinary touch pad. The distance between the track, the common plane and the drilled area should be greater than 0.5 mm. The copper must be poured as firmly as possible. Avoid pouring copper on small grids.

5. The inner layer of the gold finger must be all poured copper to avoid thinning of the board at the gold finger. Avoid choosing laminated structures with thin plates.

6. Those thin long, poorly grounded ground copper will have an antenna effect, which will cause poor EMC problems. Therefore, we should try to avoid causing broken copper when coating copper, such as causing broken copper can be removed.

7. Isolated (dead zone) copper problem, isolated copper if relatively small equivalent to broken copper can be deleted. If it is large, it can be defined as a place to add through the hole treatment, at this time there is no isolated copper.

8. Refer to the product design manual and apply copper coating near the antenna. Any interference or interference with the antenna must be avoided when pouring fake copper.

What is a breadboard?

A breadboard is a board designed and manufactured for solderless experiments on electronic circuits. It has many small jacks, allowing various electronic components to be inserted or removed as needed, eliminating the soldering steps, saving circuit assembly time, and components can be reused, which is very suitable for electronic circuit assembly, debugging and training.

The original intention of the breadboard was to encourage innovation and simplify the learning process of electronic circuits. Its main features include:

No soldering design: users can directly insert electronic components into the jacks of the breadboard without soldering, which greatly reduces the difficulty and complexity of electronic circuit production.

‌Components are reusable‌: Due to the solderless design, users can replace or adjust components in the circuit at any time without re-soldering, which is very beneficial for experiments and learning.

‌Suitable for all kinds of electronic components‌: Whether it is resistors, capacitors, transistors or integrated circuits, they can be easily inserted into the sockets of the breadboard for experiments and tests.

‌Simple structure‌: Breadboards are usually made of plastic blocks and contain a matrix of electrical sockets inside. These sockets are connected within the board, usually in rows of five sockets, forming a complete circuit path.

Why is it called a breadboard?

The reason why the breadboard got its name can be traced back to the era of vacuum tube circuits. At that time, most of the circuit components were large in size, and people usually fixed them to a piece of bread-cutting wood for connection by screws and nails. As the size of circuit components decreased, the name of the breadboard remained.

The origin of this name reflects the historical evolution and technological progress in the field of electronic production, and also reflects the intimacy and recognition of electronic production enthusiasts for this tool.

The original intention of the design of breadboard is to facilitate the assembly, debugging and training of electronic circuits. By providing many small jacks, various electronic components can be inserted or unplugged at will, thus eliminating the trouble of welding, saving the assembly time of the circuit, and the components can be reused, which is very suitable for the non-welding experiment of electronic circuits.

What is a breadboard used for?

Breadboards are mainly used for the design and manufacture of non-welding experiments of electronic circuits. ‌

A breadboard is a board designed and manufactured for the non-welding experiment of electronic circuits. Its characteristics are that there are many small jacks on the board, allowing various electronic components to be inserted or unplugged at will as needed, thus eliminating the welding process and saving the assembly time of the circuit.

In addition, since the components can be reused, breadboards are very suitable for the assembly, debugging and training of electronic circuits. This tool is a must-have for electronic production enthusiasts, and is widely used in electronic engineering, communication engineering, automatic control and other fields.

In practical applications, breadboards can be used for simulation testing and verification in the circuit design stage, as well as for transferring circuits to PCB boards for mass production in the production and manufacturing stage.

In the fields of education and research, breadboards help students and researchers better understand electronic technology and circuit design principles. It can also be used for the development and production of DIY electronic products, robots and other fields, and has a wide range of application prospects.

What types of breadboards are there?

1. Solderless breadboard:

This is the most common type. It consists of many small jacks inside, and the circuit is connected by inserting the pins of electronic components. No soldering is required, which is convenient and fast, suitable for beginners and quick circuit construction and debugging.

There are different specifications and sizes, such as small breadboards are suitable for simple circuit experiments, and large breadboards can accommodate more components to build more complex circuits.

2. Solderless breadboard:

The function is similar to that of the solderless breadboard, and electronic components can be connected without soldering. Usually with colored marking lines or areas, it is easy to distinguish different circuit parts and plan component layout.

Some solderless breadboards also come with power bars and ground bars, which are convenient for providing power and ground connections for the circuit.

3. Multi-hole breadboard:

There are more jacks and a denser layout. More electronic components can be connected, which is suitable for building complex circuits.

Some multi-hole breadboards are also designed with special structures, such as grooves or slots, to facilitate the fixing of wires and components and make the circuit more stable.

4. Breadboard with power supply

The integrated power module can directly provide stable power to the circuit without the need to connect an additional power adapter or battery pack.

The power supply part usually has an adjustable voltage function to meet the power requirements of different electronic components.

5. Transparent breadboard

Made of transparent materials, it is convenient to observe the connection status and component layout inside the circuit, which is very helpful for teaching and circuit debugging.

The appearance of the transparent breadboard is beautiful, which can increase the fun and visualization of circuit construction.

What is a “solderless” breadboard?

A solderless breadboard (also called a solderless test board) is a method that provides convenient interconnection of electronic components without the need for soldering. ‌This breadboard consists of a series of U-shaped metal contacts that are located below the hole grid in the electrically insulating shell.

The component leads and the wire segments inserted through the holes are held under spring tension by the contacts below, thus achieving a solderless connection. Solderless breadboards are particularly suitable for electronic circuit experiments in hobby, education or development environments because they allow users to quickly and easily build and reconfigure circuits while saving the time and cost of soldering.

In addition, solderless breadboards also support the reuse of components, which is very beneficial for learning and training. However, it should be noted that although solderless breadboards provide great convenience, they do not provide a mechanically sturdy interconnection, have limited power handling capabilities, and are not suitable for high-speed circuit applications.

What are the advantages and disadvantages of a breadboard?

The advantages of breadboards are:

1. Convenient and fast operation:

No need to solder, electronic components can be directly inserted into the jacks of the breadboard for circuit connection, which greatly saves the time and workload of circuit construction.

If a connection error is found during the insertion of the component, the component can be easily pulled out and reinserted without damage, reducing the cost and risk of circuit construction.

2. High safety:

Compared with soldered circuits, breadboards do not have safety issues such as burns and electric shocks that may occur during soldering, and are particularly suitable for beginners and students.

There is no need to worry about components being damaged due to improper soldering, which reduces safety hazards in circuit experiments.

3. Suitable for beginners:

For beginners of electronic circuits, breadboard is an ideal learning tool. It can help beginners quickly understand the basic principles and connection methods of circuits, enhance the perceptual understanding of electronic circuits through practical operations, and improve the interest and efficiency of learning.

4. Easy to observe and debug:

The structure of the breadboard is relatively simple, and the circuit connection is clearly visible, which is convenient for users to observe the connection of the circuit and the layout of components.

The advantages of breadboard are:

1. Poor connection stability:

The contact between the jacks on the breadboard and the component pins may not be tight enough, and it is easy to have a virtual connection. Especially after transportation, movement or long-term use, the jacks may become loose, resulting in unstable circuit connection and affecting the normal operation of the circuit.

2. Not suitable for complex circuits:

The number and layout of the jacks of the breadboard are limited. When the number of components in the circuit is large or the circuit structure is complex, the breadboard may not provide enough jacks to connect all the components, limiting the scale and complexity of the circuit.

When there are many connecting wires on the breadboard, it is easy to have chaotic lines, which increases the difficulty of circuit debugging and troubleshooting.

3. Poor high-frequency performance:

The structure and material of the breadboard determine that its high-frequency performance is poor, and it is not suitable for the transmission and processing of high-frequency signals. In high-frequency circuits, the transmission of signals will be affected by the jacks and connecting wires on the breadboard, resulting in signal distortion, attenuation and other problems.

4. Limited current carrying capacity:

The current carrying capacity of the connecting wires and jacks on the breadboard is limited. For high-power electronic components, it may not provide enough current, causing the components to not work properly or damage the breadboard.

Conclusion:

Breadboards are an indispensable tool in the world of electronics. From experiments to troubleshooting, breadboards are an indispensable part of circuit design. They can easily handle modifications, are cost-effective, and are reusable, making them a mainstream product in the electronics field.

What is the schematic file for PCB?

The schematic file is the foundation of any PCB design. It represents the logical connections and relationships between different components in the circuit. Think of it as a map showing how each component, such as resistors, capacitors, and microcontrollers, is connected to form a functional circuit.

What file type is used for PCB schematic drawings?

When creating a PCB, the schematic file is the first step. It is used to document the design and is essential to ensure that the final product functions as expected. Engineers use specialized software to create these schematic files, which can then be converted into the layout of the physical PCB.

What is PCB CAD file?

‌PCB CAD files‌ are files directly output or saved by EDA software for PCB design. These files contain information about each layer of the PCB, network connection information, component information, etc. They are very comprehensive and contain almost all the information of the circuit board.

This format is mainly used for the storage and exchange of circuit board design, and contains information such as the layout, connection, pad, and drilling of each component on the circuit board.

In circuit board design, designers use circuit board design software to draw circuit schematics, layout, connection, component placement, etc., and finally generate a PCB file, and then load the file onto the circuit board to realize the production of the circuit board.

In addition, PCB CAD files play an important role in the offline programming of SMT placement machines. Offline programming refers to the work of compiling SMT placement programs on a computer using offline programming software and PCB CAD design files.

This programming method can save online programming time, thereby reducing the downtime of the entire PCBA processing and improving the utilization of equipment. Offline programming software is often used in automated production processes to ensure efficient and accurate completion of the placement of electronic components.

What files are needed to make a PCB?

Creating a PCB is a multi-step process involving multiple different files, each with its own unique purpose.

1. Schematic file (.sch, .dsn): represents the logical connection of the circuit and is the blueprint of the entire PCB design process.

2. Netlist file (.net, .xml): generated based on the schematic, lists all components and their connections.

3. Gerber file (.gbr, .pho): Gerber file is the most important file for manufacturing PCB. Define each layer of the PCB, including copper wire, solder mask and silk screen printing layer, each layer of the PCB requires its own Gerber file.

4. Drill file (.drill, .drl): specifies the location of the holes drilled on the PCB. It includes information on the size and location of each hole.

5. Bill of Materials (BOM, .bom, .csv): BOM lists all the components required to assemble the PCB. Including part number, quantity and other details required for procurement.

6. Pick and place file (.txt, .csv): used in the assembly process to specify the precise location of each component on the circuit board.

What is the file type for circuit schematic?

The file type for a circuit schematic can vary depending on the software used to create it.

1. .SCH: This is the most common file extension for schematic files.

2. .DSN: This is another standard for schematic files.

3. .PDF: Although PDF is not a design file, it is often used to share schematics for review. It provides a non-editable version of the schematic that can be easily viewed.

4. .XML: Some tools export schematics as XML files for compatibility with other software. This format is useful for exchanging data between different design tools.

5. .PNG/.JPG: Image formats such as PNG or JPG are sometimes used to share simple schematics. These are not editable, but can provide a quick way to visualize the circuit.

What does a Gerber file contain?

Gerber is actually a description file that focuses more on PCB manufacturing and production. It should be said that it was originally designed for plotters. Therefore, the content of Gerber basically includes the information required for PCB manufacturing, such as copper foil circuit layer, solder mask layer, silk screen layer, legend layer, drill layer, etc. Even solder paste printing layer, image recognition layer, annotations and production notes can be included in it in layers.

Advantages and Disadvantages of Gerber Files

Gerber files are not suitable for being used as a storage file format for current PCB design. Because the Gerber file format does not contain the connection information between the various circuit layers of the PCB.

If you look closely at the Gerber file structure, you will find that each layer is a small file, which means that the layers of Gerber are independent and unrelated to each other. They are like independent drawings. This feature had little impact on wiring engineers when PCBs were only single-sided or double-sided in the early days, but it is very disadvantageous in design, operation, debugging and verification for the increasingly complex multi-layer PCBs. Therefore, almost no one uses Gerber files as the file format for PCB design.

Because the amount of information in Gerber files is small, its file size is much smaller than other design files drawn by EDA or CAD software. In addition, its format is more irreversible in design and protects the original design. In addition, its vector image layered format is still very suitable for use in PCB manufacturing. Today, PCB production generally follows this layer to divide the process into different stages for production, so Gerber files are still widely used in PCB production.

Therefore, some design companies with high confidentiality requirements will convert the design files into Gerber before sending them to the PCB factory for production, trying to keep confidentiality.

Conclusion:

For anyone working in the electronics industry, it is essential to understand the various file types used in PCB design. From the initial schematic file to the final Gerber file, every step in the design process relies on accurate and compatible files. BEST Technology has a professional PCB design team with rich experience in different PCB designs. We can solve all your PCB design problems.

What is led light circuit board?

LED light circuit board is the abbreviation of printed circuit board, which is mainly used to carry and connect electronic components of LED lamps. ‌LED light circuit board is usually made of aluminum substrate and FR-4 fiberglass circuit board, where the LED aluminum substrate is printed on the aluminum plane with good thermal conductivity, and then the electronic components are soldered on it. ‌This design helps to improve the heat dissipation performance and stability of LED lamps, and ensure that the LED lamps can work stably for a long time.

What is an LED circuit board? How to make it?

The main function of LED light circuit board is to provide power to LED lamp beads and control the brightness and color of its LED lamp beads. In order to light up the LED lamp beads, an LED driving circuit is required, which includes constant voltage driving, constant current driving, PWM driving and other methods, which are usually integrated on the small circuit board of the LED lamp.

In addition, the design and manufacture of the LED lamp circuit board take into account the characteristics of LED, such as long life, high light efficiency, no radiation and low power consumption. Compared with traditional light sources, such as incandescent lamps and fluorescent lamps, LED lamps have significant advantages in efficiency, life and environmental protection.

How to make led light circuit board?

The process of making LED lamp circuit boards involves multiple steps, including welding, self-inspection, mutual inspection, cleaning, friction, wiring, etc.

Determine the direction of the lamp: the front side is facing up, and the side with the black rectangle is the negative end.

Determine the direction of the circuit board: the front side is facing up, and the end with two internal and external wiring ports is the upper left corner.

Welding: Carefully weld each solder joint to ensure fullness, cleanness, and no false soldering or leaking. ‌

Self-inspection: After completing the welding, first check whether there is a cold solder joint, leaking solder joint, etc. Use a multimeter to touch the positive and negative terminals of the circuit board to check whether the LED lights are on at the same time. ‌

Mutual inspection: After the self-inspection, it will be handed over to the person in charge for inspection. Only with the consent of the person in charge can it flow into the next process. ‌

Cleaning: Use 95% alcohol to scrub the circuit board to remove residues and keep the circuit board clean.

Friction: Use fine sandpaper (coarse sandpaper if necessary) to grind off the burrs on the edge of the circuit board so that the circuit board can be placed flatly in the fixing seat. ‌

Wiring: Use blue and black thin wires to connect the circuit board. The wiring point close to the inner circle is negative and connected to the black wire; the wiring point close to the outer circle is positive and connected to the red wire. ‌ Make sure the wires are connected from the back to the front. ‌

Self-check and mutual check: Check the wiring to ensure that each wire passes through the pad, the length of the wires on both sides of the pad that remain on the surface should be as short as possible, and the thin wires will not break or loosen when gently pulled. ‌‌

Through the above operations, the production of the LED lamp circuit board can be completed. ‌Each step is crucial, especially the welding and wiring parts. It is necessary to ensure the quality of the welding points and the correct connection of the wires to ensure the normal operation of the circuit board and the normal lighting of the LED lamp.

Why do you need a resistor with an LED?

When using LED, a resistor needs to be connected in series to control the current, prevent excessive current from damaging the LED, and ensure that the LED can emit light normally. ‌

LED is a semiconductor device that can directly convert electrical energy into light energy. Due to its special material properties, LED is very sensitive to current, and excessive or insufficient current may cause the LED to malfunction or be damaged.

Therefore, when the LED is connected to the power supply, a resistor is needed to limit the current to ensure that the LED can work stably and safely.

The main function of this resistor is voltage division and current limiting. It is used to adjust the current passing through the LED to prevent the LED from burning out due to excessive current, while also ensuring that the LED can emit light of appropriate brightness.

Specifically, when current passes through the LED, the resistor will produce a certain voltage drop, thereby reducing the voltage applied to both ends of the LED, thereby controlling the current passing through the LED.

What resistor to use with LED?

Use an LED resistor calculator to help determine the required resistor value. ‌

When using LEDs, in order to protect the LED and ensure its normal operation, it is usually necessary to limit the current by connecting an appropriate resistor in series. This is because each LED has a maximum current value, exceeding which may cause the LED to be damaged.

Using an LED resistor calculator can help you determine the required resistor value to ensure that the current does not exceed the maximum tolerance of the LED.

By entering the relevant parameters of the LED (such as the rated current and voltage), the calculator will automatically calculate the required resistor value to protect the LED from overcurrent damage.

This method is a common practice and is applicable to any situation where a number of LEDs are used in series. In this way, the safe operation of the LED can be ensured while avoiding damage caused by excessive current.‌

How to improve the heat dissipation performance of LED light circuit boards?

The key to improving the heat dissipation performance of LED light circuit boards is to optimize the heat dissipation path, use efficient heat dissipation materials, and adopt advanced heat dissipation technology.

Optimize the heat dissipation path:

Understanding the heat transfer path of the heat generated by LED components is the first step to improve heat dissipation performance. Heat moves from the LED components through the package wires to the circuit board, and then dissipates through the heat sink.

The heat dissipation efficiency can be effectively improved by using materials with good thermal conductivity, expanding the cross-sectional area of the path (such as using thick copper wire), and applying thermal lubricants to reduce the gaps in the connection parts.

Use efficient heat dissipation materials:

Metals such as copper and aluminum are often used to make heat sinks because of their good thermal conductivity. In addition, new materials such as graphene are also used to make heat sinks because of their excellent thermal conductivity. These materials can significantly improve heat dissipation efficiency. ‌

Adopting advanced heat dissipation technology:

Micro-groove group composite phase change integrated cooling technology is an advanced heat dissipation technology. It effectively removes the heat of high-power electronic devices by changing the closed-circulation cooling medium into a nano-scale water film and utilizing its strong evaporation ability and latent heat exchange ability.

As an excellent thermal conductive medium, thermal conductive silicone grease has excellent electrical insulation and thermal conductivity. It can penetrate into the tiny depressions on the metal surface, increase the contact area, and improve the efficiency of heat conduction from the LED chip to the aluminum substrate.

Are LED PCBs only used in lighting systems?

The application range of LED PCB (printed circuit board) is far more than lighting systems. In addition to lighting systems, LED PCB is also widely used in other fields. For example, LED lamps are one of the most common products using LED PCBs. Whether it is home lighting, commercial lighting or outdoor lighting, LED lamps occupy a large market share.

Compared with traditional incandescent lamps and energy-saving lamps, LED lamps have higher luminous efficiency, longer service life and lower energy consumption. They also have features such as dimming and color change, which can meet the needs of different scenarios. ‌

In addition, LED PCB is also used in LED display screens, LED backlight sources and automotive lighting. LED display screens provide high-definition and high-brightness display effects in large-scale events such as sports events, concerts, and exhibitions, bringing a shocking visual experience to the audience.

LED backlight sources have become the mainstream choice in electronic products such as LCD monitors, mobile phones, and tablet computers. Compared with traditional cold cathode fluorescent lamps, LED backlight sources have higher brightness, longer service life and lower energy consumption. At the same time, they can achieve local dimming, improve display effects and reduce energy consumption.‌

In the field of automotive lighting, with the advancement of automotive lighting technology, more and more cars are beginning to use LED lamps. Compared with traditional halogen and xenon lamps, LED car lights have higher brightness, longer service life, lower energy consumption, faster response speed and better heat dissipation performance, which improves driving safety. ‌

From this we can know that the application of LED PCB is not limited to lighting systems, but is widely used in many fields, including but not limited to lighting, display technology, backlight sources of electronic products, and automotive lighting. ‌

Conclusion:

Designing PCB for LED lights is a complex but critical task that requires careful consideration of various influencing factors, from the selection of manufacturing materials to the testing of thermal conductivity and the quality testing of finished products. Choosing Best Technology has expert design assistance and reliable manufacturing processes, which will allow you to obtain the best results for LED light PCB design. ‌

What is the average cost of a PCB?

The average cost of PCB varies due to many factors, and there is no fixed value. ‌

The cost of PCB is mainly composed of the following parts:

1. Substrate cost: Substrate is the basic component of PCB. Common material types include FR4, CEM-1, aluminum substrate, etc. The price of different types of substrates varies greatly.

How much does a custom PCB cost per unit? How to calculate?

2. Process cost: The manufacturing process of PCB includes inner layer circuit production, lamination, drilling, electroplating, outer layer circuit production, solder mask treatment, text printing and surface treatment. Each step requires professional equipment and technicians to operate, so there will be corresponding costs.

3. Inspection cost: After the PCB is manufactured, a series of tests are required to ensure its quality, including electrical performance testing, reliability testing, and appearance inspection.

4. Other additional expenses: In addition to the above main costs, there are some additional expenses to consider, such as special design or modification services may require additional design fees. In addition, additional costs such as packaging, transportation, and taxes also need to be taken into consideration.

In summary, the cost of PCB is composed of multiple aspects, including substrate cost, process cost, inspection cost, and other additional expenses, which need to be comprehensively evaluated based on specific board type, number of layers, drilling amount, surface treatment process, and other factors.

How to calculate PCB design cost?

‌Material cost is an important part of design cost, including board, solder mask ink, chemical agents, etc. These costs are relatively easy to calculate, but the additional losses caused by material loss and risks during storage and use need to be considered.

‌Process cost covers equipment use time, worker wages, energy consumption, etc. When calculating the cost of equipment use, the frequency and duration of equipment use and the total investment cost should be taken into account.

‌Equipment depreciation and maintenance costs‌ are also a part that cannot be ignored, including the original price of the equipment, accumulated depreciation, and maintenance and repair costs.

‌Other related costs‌ such as administrative costs, quality control costs, and R&D costs, although more difficult to calculate, have a significant impact on the total cost of the project.

Material costs include substrate materials, circuit board materials, and copper foil, processing costs involve drilling, copper plating, graphic etching and other processes, and labor costs include direct and indirect labor costs. Through these calculations, plus a reasonable profit margin, the final PCB quotation is obtained.

What is the most expensive PCB?

The most expensive PCB may be an electroless nickel electroless palladium immersion gold (ENEPIG) PCB.

This electroplating material has a copper-nickel-palladium-gold layer structure that can be directly bonded to the electroplating layer through wires. The last layer of gold is very thin, just like electroless nickel immersion gold (ENIG).

The gold layer is soft, so excessive mechanical damage or deep scratches may expose the palladium layer. Although the gold layer is soft, ENEPIG’s PCB is often considered the first choice in high-end applications due to its high-quality electrical performance and durability, so its cost is relatively high.

In addition, the production of high-end precision PCB circuit boards is also expensive, including multi-layer boards, boards with BGA, HDI circuit boards, etc. These products usually require more complex production processes and higher material quality, so the cost is also relatively high.

How much does PCB assembly cost per component?

The PCB assembly cost of each component is composed of multiple factors, including board costs, processing costs, testing costs, and other additional costs. ‌

Board costs are an important part of PCB assembly costs. The types of boards, such as FR4, CEM-1, aluminum substrates, etc., have large price differences.

FR4 boards are widely used due to their excellent electrical and processing properties, but their prices are affected by fluctuations in the prices of raw materials such as international copper prices, epoxy resins, and glass fiber cloth.

Aluminum substrates are favored in certain specific applications due to their good heat dissipation performance, but their prices are usually much higher than FR4 boards.

‌Processing costs‌ cover multiple links in the PCB manufacturing process, such as inner layer circuit production, lamination, drilling, electroplating, outer layer circuit production, solder mask, text printing and surface treatment.

Each link requires professional equipment and technicians to operate, so there will be corresponding costs. In particular, the costs of steps such as drilling and electroplating will vary according to factors such as the number of holes, the area and thickness of the electroplating.

‌Testing costs‌ are an important link to ensure the quality of PCBs. After the production is completed, the PCB needs to undergo a series of tests, including electrical testing, reliability testing, and appearance inspection.

These tests require not only professional testing equipment, but also experienced testers to operate and analyze the results, so certain costs will also be incurred.

‌Other additional costs‌ include additional design fees that PCB manufacturers may charge if customers require special design or modification services. In addition, there are some additional costs such as packaging, transportation and taxes that need to be taken into account.

In summary, the PCB assembly cost of each component is determined by the board cost, processing cost, testing cost and other additional costs, and the specific cost will vary according to the specific needs of the project and the manufacturer’s quotation.

What is the cheapest PCB finish?

The cheapest PCB surface treatment process is hot air solder leveling (HASL). ‌

HASL is a commonly used PCB surface treatment process, which is divided into lead-containing tin and lead-free tin. It is one of the most commonly used and relatively inexpensive surface treatment processes.

This process is to immerse the circuit board in molten solder (tin/lead), and then the solder covers all exposed copper surfaces on the board to form a HASL surface finish.

HASL is not only one of the cheapest types of PCB surface treatment, but its process temperature is 250℃, the shelf life can reach 12 months, and the surface treatment thickness ranges from 1-40um, making it an economical and practical choice.

In addition, HASL is divided into leaded and lead-free. Although the leaded version is gradually replaced by the lead-free version for environmental reasons, the lead-free HASL still maintains a low cost, making it the preferred choice for projects with limited budgets‌.‌

Do vias make PCBs more expensive?

Vias may indeed increase the cost of PCBs. ‌

Vias are an important part of multi-layer PCB boards, and they play a key role in the design and manufacturing process of circuit boards. Vias can be divided into buried vias, blind vias and through holes. Among them, through holes pass through the entire circuit board and are used to achieve internal interconnection or component installation and positioning. They are the most commonly used types.

The number and type of vias directly affect the cost of the PCB, because each via needs to go through processes such as drilling and electroplating, which account for a considerable part of the cost of PCB board manufacturing.

Factors that affect the cost of PCBs also include the size of the vias. The smaller the via, the greater the manufacturing difficulty, and the corresponding increase in cost.

In addition, different types of vias require different processing technologies and materials, which also affects the cost. For example, the processing processes and difficulties of blind and buried vias are different, resulting in different prices.

The price difference between blind and buried vias is mainly caused by many factors such as material cost, complexity of processing process and difficulty of processing. Blind vias require double-sided or multi-layer composite boards, which have higher material costs, while buried vias can be processed using single-sided boards, which have relatively low costs.

In addition, the processing processes of blind vias are diverse, the process is complex, and higher technology and cost are required. The processing time is long and the manufacturing cost is relatively high.

In summary, the number, type, size and processing method of vias will affect the cost of PCB. When designing PCB, it is necessary to find a balance between function and cost to optimize the design and cost control.

Conclusion:

The unit cost of PCB is affected by many factors, including but not limited to the number of layers, material, drilling amount, and surface treatment process of the board. BEST Technology has many years of experience in PCB board design and has skilled experience in handling various factors that affect PCB cost. It can help you find the best way to solve all your concerns about PCB cost.

What files do I need to make a PCB?

Making PCBs (printed circuit boards) requires a series of files to ensure the smooth progress of the manufacturing process and the quality of the product.

‌Gerber file‌: This is the most common and crucial file in PCB manufacturing. It contains the geometric information of each layer of the PCB, such as copper lines, pads, solder mask layers and silk screen layers, and also includes separate files for each PCB layer, such as top copper, bottom copper, solder mask, silk screen layer, etc. ‌

What file types are used for PCB design?

‌Drill file‌: Provides drilling coordinates and size information for PCBs, and specifies the aperture size of components, vias and mounting holes. Drill files are usually generated in Excellon format or as separate ASCII files‌.

‌Bill of Materials (BOM): A BOM is a detailed list of all components used in a PCB design, including information such as part number, component value, description, and quantity, which helps ensure that all required components are correctly sourced and placed on the PCB.

‌Center Coordinate File: Also known as a pick and place file, it provides coordinate and orientation information for each component on the PCB and is essential for the automated assembly process. Center coordinate files are usually provided in CSV format.

‌Fabrication Drawing: This is an engineering drawing that includes key information about the PCB, such as board dimensions, drill hole dimensions, layer stackup, tolerances, surface finish, and other manufacturing-related details, which serves as a reference for PCB manufacturers during the production process.

‌Assembly Drawing: Provides additional information for the PCB assembly process, including component placement details, reference numbers, orientation, and any special instructions for assembly technicians.

In addition, depending on the specific design and production needs, other documents may also be required, such as circuit diagrams, special layer files, installation instructions and precautions, etc. ‌ The preparation and provision of these documents is a key step in ensuring a smooth PCB production process.

What are Gerber files? What information do they contain?

Gerber files are a series of ASCII vector format files that define PCB design specifications. They are generated using electronic design automation (EDA) or computer-aided design (CAD) tools and provide information such as board configuration parameters, aperture descriptions, XY coordinate locations, and drawing instructions.

Configuration details include the size and shape of the PCB to be manufactured. Each layer of the board information is recorded in a different file to define components such as copper traces, pads, vias, solder mask, silk screen, and logos. The Gerber file indicates the XY coordinate location of each geometric shape and uses instructions to draw these shapes on the physical board.

The basic components of the Gerber file include: board size, shape, top assembly, top silk screen, top solder mask, top paste, top copper, internal signals, inner layers, bottom copper, bottom paste, bottom solder mask, bottom silk screen, bottom assembly, and manufacturing information (providing stackup, drilling details, cutting, etc.).

Gerber files generated by computer-aided manufacturing (CAM) tools have user-selected extensions, usually using project naming such as “.TOP” for top layer, “.BOT” for bottom layer, and “.drl” for drill data.

How is a PCB designed?

PCB design is a complex process that involves multiple steps and considerations to ensure the functionality and reliability of the final product.

‌Schematic Design‌: First, you need to prepare a schematic and component library. The schematic is the blueprint of the circuit design, while the component library contains information about the various components used in the circuit.

‌Component Symbols and Packages‌: The symbol of the component is used to represent the component in the schematic, while the package defines the physical form of the component on the PCB. The component symbol is used in the schematic design stage, while the package is used in the PCB layout and routing stages.

How is a PCB designed?

‌PCB Layout‌: The layout stage involves placing electronic components on the PCB, and factors that need to be considered include the orientation, size, and relative position of the components.

‌Routing‌: After the layout is completed, the next step is the routing stage, which is to connect the various components according to the needs of the circuit.

‌DRC Check‌: Design rule checking (DRC) is performed during the design process to ensure that the design complies with predetermined electrical and physical rules. This includes checking for shorts, open circuits, and other possible design errors.

‌Solder mask and solder paste layer‌: The solder mask is used to prevent unnecessary soldering, while the solder paste layer is used to specify solder joints. The correct design of these layers is critical to ensuring the reliability and manufacturability of the circuit board.

‌Network and DRC Check‌: In the final stage of design, network checks are performed to ensure that all components are properly connected, while DRC checks are performed to verify that the design complies with all electrical and physical rules.

‌Through the above steps, designers are able to transform the circuit design in the schematic into an actual, manufacturable PCB. This process requires comprehensive consideration of multiple factors such as the functionality, reliability, and manufacturing cost of the circuit.

‌What is the schematic file for PCB?

‌PCB schematic files are the main files used for circuit design, analysis, and debugging. They mainly show the electrical connection relationship between electronic components, but do not reflect the actual physical location of these components on the PCB board. ‌

Schematic Diagram is the basis of circuit design. It uses symbols and lines to express the connection and working principle of the circuit in a concise and clear manner, and pays more attention to the functional expression of the circuit.

Schematic diagram does not involve the specific layout and wiring of electronic components on the PCB board, so it focuses on the logical representation of the circuit rather than the physical implementation. ‌

In contrast, PCB design files plan the precise location and wiring of electronic components on the PCB board in detail, taking into account the connectivity of the circuit, and also comprehensively considering factors such as signal integrity, power distribution, thermal design, and mechanical strength. ‌

These design files are the main files used to manufacture actual electronic devices, including PCB layout and PCB wiring. The layout determines the location of electronic components on the circuit board, while the wiring involves the electrical connection between components. ‌

In general, schematic files and PCB design files play different roles in the design and manufacturing process of electronic products. The former focuses on the expression of circuit logic and function, while the latter focuses on converting this logic into actual physical implementation, including the specific location and connection method of components. ‌

What is the difference between PCB design and schematic design?

The main difference between PCB design and schematic design lies in their purpose, content and application scenarios. ‌

‌Purpose and content‌:

Schematic design focuses on describing the logical relationship and electrical performance of the circuit, using graphic symbols to display power, components and connections, and can clearly show the logical relationship of the internal circuit of the electronic device. It is mainly used for circuit analysis and design, helping to understand the working principle of the equipment and perform fault diagnosis‌.

PCB design focuses on describing the actual physical size, position and wiring of components, and is the actual circuit board layout and wiring design based on the schematic diagram. It is mainly used to guide the manufacture and assembly of PCBs, reflecting the actual layout and wiring of electronic equipment‌.

‌Application scenarios‌:

Schematic design plays an important role in the process of R&D, debugging and maintenance, and is a key tool for understanding the working principle of the equipment and performing fault diagnosis‌.

PCB design files are an important basis for the actual PCB board manufacturing and subsequent assembly, debugging and other processes‌.

In short, schematic design is the basis of electronic product development. It provides information such as the logical relationship and electrical performance of the circuit, while PCB design is the key link to convert the schematic into an actual circuit board. It is necessary to design components layout and wiring according to the requirements of the schematic.

What is a PCB stencil file?

A PCB stencil file is a pre-designed file template used to quickly generate PCB design files containing specific information.

These template files usually contain basic information such as board size, board layer settings, grid settings, and title bar settings. Users can quickly generate new PCB design files based on these templates, thereby speeding up the design process.

By using these templates, designers can avoid designing these basic settings from scratch, saving time and energy, and focusing on more complex circuit design details.

Conclusion:

There are many types of PCB design files, among which Gerber files are the most important. The information they contain is the most and the most important. The final quality of the PCB circuit board depends on the first step of design. BEST Technology has very professional PCB designers who have many years of industry experience and can meet all your needs.

1. Single-sided board:

On the most basic printed circuit board, parts are concentrated on one side and wires are concentrated on the other side. Because wires only appear on one side, this type of printed circuit board is called a single-sided board. Because single-sided boards have many strict restrictions on designing circuits (because there is only one side, wiring cannot cross and must go around a separate path), early circuits used this type of circuit board.

2. Double-sided board

This type of circuit board has wiring on both sides. In order to connect the wires on both sides, there must be a proper circuit connection between the two sides. This connection between the circuits is called a guide hole. A guide hole is a small hole filled or coated with metal on a printed circuit board, which can be connected to the wires on both sides. Because the area of a double-sided board is doubled that of a single-sided board, and the wiring can be interlaced (can go around to the other side), double-sided boards can be used on more complex circuits than single-sided boards.

3. Multilayer board:

In order to increase the area that can be wired, multilayer boards use more single- or double-sided wiring boards. Multilayer boards use several double-sided boards, and put an insulating layer between each layer of boards and glue them firmly. The number of layers of the circuit board represents how many independent wiring layers there are, usually an even number of layers, and includes the two outermost layers.

4. Flexible PCB board

Flexible PCB board is a printed circuit board made of a flexible substrate. Its advantage is that it can be bent, which is convenient for the assembly of electrical components. Flexible circuit board, flexible PCB, flexible circuit and multi-function printed circuit are other names for these circuit boards. These printed circuit boards are made using the same components as rigid printed circuit boards. The main difference is that the circuit board is designed to bend to the desired shape throughout the application process. These PCBs are available in single-sided, double-sided, and multi-layer configurations. This helps reduce the complexity of unit assembly.

5. Rigid PCB Board

Rigid PCB is a circuit board that cannot be twisted or folded. The base material of the board is a rigid substrate, which gives the board rigidity and strength. They are composed of multiple layers, including substrate layers, copper layers, solder mask layers, and silk screen layers, which are bonded together by adhesives and heat. While some circuit boards are single-sided, double-sided, or multi-layered, rigid PCBs can be any of these as needed. However, once made, they cannot be modified or changed.

6. Rigid-Flex Board

Rigid-Flex Board is a hybrid circuit board that combines elements of flexible and rigid circuit boards to form a foldable or continuously bendable circuit board, which is usually molded into a curved shape or curve during the manufacturing process.

The flexible portion of the circuit board is often used for interconnections between rigid circuit boards, allowing narrower wires to take up less space, thereby reducing the size of the circuit board. Using flexible PCBs for interconnections often eliminates the need for bulky and heavy connectors, making rigid-flex boards lighter. The design of rigid-flex boards is slightly more complicated because these boards are 3D constructed, allowing the board to be folded or twisted to produce the shape required for the product.

7. High-frequency PCB board

High-frequency circuits refer to the overall circuit board design, not the other types of circuit board structures we described earlier. These PCBs are designed to conduct signals over 1 GHz.

High-frequency boards mostly use FR4-grade glass-reinforced epoxy boards, polyphenylene ether (PPO) resins, and Teflon, but Teflon has a low and stable Dk value, low dielectric loss, low hygroscopicity, and is slightly more expensive.

When designing high-frequency circuits, various factors must be considered, such as Dk value, dissipative loss, and dielectric thickness. The DK value of the substrate is an important factor to remember. Substrates with a higher probability of Dk value changes usually experience impedance changes, which affects the harmonics that make up the electrical signal, resulting in poor signal integrity.

8. Copper substrate

Copper substrate is a metal substrate with high thermal conductivity, suitable for high-frequency circuits and areas with large high and low temperature changes and heat dissipation and architectural decoration industries for precision communication equipment.

The copper substrate circuit layer requires a large current carrying capacity, and a thicker copper foil should be used, with a thickness of generally 35μm~280μm. The thermal conductive insulation layer is the core technology of the copper substrate. It is composed of core thermal conductive components and high molecular polymers, with low thermal resistance (0.15), excellent viscoelastic properties, resistance to thermal aging, and the ability to withstand mechanical and thermal stress.

The copper substrate metal base is the supporting member of the copper substrate, which is required to have high thermal conductivity. It is generally a copper plate, and a copper plate can also be used (where the copper plate can provide better thermal conductivity). It is suitable for conventional mechanical processing such as drilling, punching and cutting.

9. Aluminum-based PCB board

The design of aluminum-based PCB circuits is similar to that of copper-based PCBs, but the substrate material of aluminum-based PCBs is aluminum metal, rather than the standard glass fiber used in most circuits.

The aluminum layer is reinforced with the least heat-resistant insulation material, which means less heat is transferred from the insulation material to the backing. After applying the insulation layer, another layer of copper is required.

10. High Density Interconnect (HDI) PCB

Among the many types of PCBs, HDI PCB is a circuit with multiple interconnections that takes up very little space. HDI components are mounted close to each other, minimizing PCB space while maintaining high functionality. Boards containing 120-160 pins per square inch are classified as HDI PCBs.

HDI designs integrate dense device mounting and multi-purpose wiring. With the help of microvias, buried vias, and blind vias, compact circuits can be made, minimizing drilling to copper. For the electrical requirements of high-speed signals, HDI PCBs must have high-frequency conduction capabilities, impedance control, and minimal redundant radiation.

11. Thick Copper PCB

Thick copper PCB is also called heavy copper PCB. Basically, it contains more than 2 ounces of copper in the inner and outer layers of the board. Heavy copper transmitters significantly increase the overall thickness of the board; thick copper boards are known for supporting high currents, high temperatures, and cyclical thermal cycles.

12. High TG PCB

Among various types of PCBs, high Tg PCBs are circuit boards designed to work at high temperatures. Glass transition temperature (Tg) is an essential element of any epoxy resin. It is basically the temperature point at which the polymer changes from a hard glass substrate to a soft rubber substrate. The substrates used to make high Tg circuit boards must be flame retardant, which means that they soften instead of burning at the glass transition point (Tg).

The higher the Tg value, the higher the temperature requirement during lamination. Under such conditions, the PCB will become hard and brittle, affecting the aperture size and related electrical properties. Standard boards will soften, deform and melt under such conditions, and their mechanical and electrical properties will be significantly reduced.

Standard FR-4 Tg is between 130-1400C, medium Tg is between 150-1600C, and high Tg is above 1700C. The higher the Tg value, the better the board’s heat, moisture and chemical resistance.

Conclusion:

PCB board types are updated and iterated with the rapid development of the industry, and various types of PCB boards have gradually evolved to cope with various application scenarios, adding corresponding materials according to the required performance. BEST Technology has various PCB types of manufacturing technology, which can meet your any type of PCB needs.

PCB Stack-up Parameter

Internal Copper Thickness After Processing

Base Foil	Min. After Processing
18um (1/2oz)	11.4um
35um (1oz)	24.9um
70um (2oz)	55.7um
105um (3oz)	86.6um
140um (4oz)	117.5um

External Copper Thickness After Plating

Base Foil	Min. Class 2	Min. Class 3
12um (3/8oz)	29.3um	34.3um
18um (1/2oz)	33.4um	38.4um
35um (1oz)	47.9um	52.9um
70um (2oz)	78.7um	83.7um
105um (3oz)	108.6um	113.6um
140um (4oz)	139.5um	144.5um

Common Prepreg (PP) Properties

Type	Thickness (mm)	Resin (%)
106	0.05	65
1080	0.075	65
2116	0.12	55
7628	0.2	46

Common Material List

Medium Tg	Shengyi S1000-H
	ITEQ IT-158
	Elite EMC-825
High Tg	Shengyi S1000-2M
	ITEQ IT-180A
	Elite EMS-827

Common Core Thickness

PCB Stack-up and Impedance Control Guidelines

Design Tips – Stack-up

1. Ensure the stack-up remains symmetric.

2. Typically, a foil build is recommended. Special core builds, like those with Rogers, are possible but less common.

3. For boards thicker than 1mm, the standard thickness tolerance is +/-10%. For 1mm boards, the standard tolerance is +/-0.1mm. Any board with a thickness ≤1mm requires approval from Best Tech.

4. The minimum dielectric thickness will be 90µm, according to IPC standards, unless otherwise specified by the FAB drawing and there are no micro vias.

5. Use a maximum of three sheets of prepreg to bond the layers.

6. While the stack-up used in production may differ slightly from the specified one, an Engineering Query (EQ) will be sent for confirmation.

7. Variations can occur due to factors like copper distribution and available materials.

8. Thicker copper foils require thicker dielectrics between layers, and the foil thickness after processing differs from the base foil thickness.

9. Additionally, variations in resin percentage for the same prepreg type can impact the final prepreg thickness.

10. When incorporating micro vias, consider the aspect ratio—recommended at 0.8:1 and advanced at 1:1—when selecting prepreg.

If you need special materials, thickness tolerances, or stack-ups, contact Best Technology for guidance. Below are some suggested stack-ups for different layers PCB.

Impedance Parameters Needed for Calculation

Symbol	Feature
H1, H2, H3..	Dielectric thickness between copper layers after pressing
Er1	Dielectric constant of prepreg or core used between copper layers.
W1	The bottom width od impedance lines, which is the customer required impedance trace width.
W2	The top width of impedance lines.
S1	The space between two differential impedance traces.
T1	Finished copper thickness, which is different with our normal definition.
C1	Solder mask thickness on material.
C2	Solder mask thickness on copper.
C3	Solder mask thickness on material between traces (C1 = C3).
CEr	Dielectric constant of solder mask. Normally use 3.4 to calculate.

Tolerance of Impedance Control

Type of Impedance	Common Requested Value	Tolerance of Impedance Control
Type of Impedance	Common Requested Value	General	Moderate	Advanced
Single/Single Coplanar	40Ω/510Ω/75Ω	+/-10%	+/-8%	+/-5%
Differential/Differential Coplanar	90Ω/100Ω/120Ω	+/-10%	+/-8%	+/-5%

Relationship between Parameters and Impedance Value

Parameters Modification		Effect on Impedance Value
Parameters	Increase/Reduce	Impacts on impedance	Impedance value increase/reduced
H (dielectric thickness)	Increase	Big	Increase
W (trace width)	Increase	Big	Reduced
S (trace space)	Increase	Big	Increase
T (copper thickness)	Increase	Low	Reduced
C (solder mask thickness)	Increase	Low	Reduced

Design tips – Impedance

When signal speeds exceed 2 GHz and timing is critical, consider using better materials such as medium, high, or ultra-high-speed options, along with flat glass styles. To ensure a reliable lamination process and prevent resin starvation, allow the factory to select the number of prepregs, prepreg styles, and resin content in the stack-up.

Key factors influencing impedance signal losses include:

1. Line Length: Signal losses are directly proportional to the line length—shorter lines result in fewer losses, while longer lines lead to greater losses.

2. Dielectric Loss: These losses can be minimized by selecting appropriate materials.

3. Copper Loss: This includes losses from the cross-sectional area (affected by stack-up design) and surface roughness, which can be reduced through material selection and proper stack-up configuration.

If you require impedance tolerances tighter than +/-10%, discuss your design possibilities with the Best Technology team.

When designing rigid-flex boards, note that separate calculations are necessary for both the rigid and flex sections of the same signal. Manufacturers will adjust the thickness and dielectric constant of the solder mask based on their solder mask properties and printing method. Variations in resin content for the same prepreg type can also affect impedance. For assistance with impedance calculations, contact Best Technology for support.

Checklist of Necessary Information for Impedance Calculations

1. Specify the type, value, and tolerance of impedance control.

2. Ensure you define the width and space of impedance traces, as well as the layers where these traces will be present, along with the layers to be considered as reference points.

3. Identify the type of material and final board thickness, and provide a reference stack-up for the design.

4. Confirm the finished copper thickness on external and internal layers, and note if any special type of solder mask is required.

5. Always request Best Technology’s stack-up before starting the routing design.

What is the standard for PCB assembly?

The standards for PCB assembly mainly include PCB panel specifications, ISO standards, IPC standards, JEDEC standards, and ROHS standards. ‌

‌PCB panel specifications‌ involve the width, shape, frame design, center distance between small boards, setting of positioning holes, arrangement of reference symbols, and positioning of large components of the panel. The panel frame should adopt a closed-loop design to ensure that the panel is fixed on the fixture without deformation.

‌ISO standards‌ emphasize key factors such as fit tolerance, surface roughness, contact area, and tightening force in PCB tight-fit installation to ensure the accuracy and stability of installation‌.

‌IPC standards‌ include IPC-7711 and IPC-A-600E, the former provides basic recommendations and guidelines for the design and manufacture of printed boards, and the latter provides acceptable conditions and practice guidelines for printed boards.

‌JEDEC standards‌ provide specifications for circuit board materials, dimensions, interfaces, etc., including material selection, dimension design, interface specifications, test methods and quality assurance.

‌ROHS standard‌ is a directive on the restriction of the use of hazardous substances, aimed at reducing the impact on the environment and human health. It stipulates the use restrictions of hazardous substances such as lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls and polybrominated diphenyl ethers.

Compliance with these standards ensures the quality, safety and environmental friendliness of PCB products, and also provides clear guidance and specifications for the design, manufacture and assembly of PCBs.

Why is PCB assembly so expensive?

The high cost of PCB assembly is mainly due to the combined influence of multiple factors. ‌

First, the production cost of PCB boards is affected by materials, design and manufacturing complexity, precision and quality, and supply chain and regional differences. PCB boards are mainly made of materials such as copper, fiberglass and epoxy resin, and the cost of these materials directly affects the price of PCB boards.

The complexity of the design and manufacturing process, including pre-processing, image transfer, electroplating, etching, inspection and trimming, and post-processing, requires precise tools and professional skills, which will also be reflected in the cost. High-precision PCB boards require higher manufacturing costs because they require more precise tools and more stringent manufacturing processes.

Details in the PCB assembly process, layer selection, and the application of HDI technology will all have an impact on the cost. Every small change may cause the cost to plummet, so if you want to save money without losing performance, you need to consider these factors comprehensively.

In addition, the welding process is also a costly link. Soldering is a key step in fixing electronic components to PCBs. This process requires heating each joint separately for welding, which is a slow and laborious process.

Finally, the price of PCBs is also affected by factors such as materials, surface processing, design standards, copper foil thickness, quality acceptance standards, and mold fees and test frames. For example, different materials, surface processing, and copper foil thickness will lead to price differences.

In summary, the high cost of PCB assembly is mainly due to the combined effect of multiple factors such as material cost, manufacturing complexity, precision and quality requirements, production needs, and specific design and quality requirements.

What does PCB stand for?

PCB stands for Printed Circuit Board. ‌

Printed circuit board (PCB), also known as printed circuit board, is an indispensable component in electronic engineering. It is the support of electronic components and also the carrier of electrical connection of electronic components.

Printed circuit boards are widely used in various electronic devices. Printed circuit boards can be divided into single-sided boards, double-sided boards, multi-layer boards, etc. according to the number of layers of circuit boards. Among them, multi-layer boards refer to printed boards with more than two layers. It consists of connecting wires on several layers of insulating substrates and pads for assembling and welding electronic components. It has the function of conducting each layer of circuits and insulating each other.

The wide application of printed circuit boards makes it possible to miniaturize and visualize the circuits of electronic devices, which plays an important role in the mass production of fixed circuits and optimizing the layout of electrical appliances. This type of circuit board uses polyimide or polyester film as the substrate, and has the characteristics of high wiring density, light weight, thin thickness and good bendability.

What is the difference between PCB and PCBA?

The main difference between PCB and PCBA lies in their definition, function, application and manufacturing process. ‌

Definition:

PCB (printed circuit board) is a basic electronic component made by electronic printing, mainly used as a support for electronic components, and does not contain any active or passive components.

PCBA (printed circuit board assembly) is a circuit board assembly with specific functions formed by soldering electronic components to PCB through processes such as SMT (surface mount technology) or THT (through-hole mounting technology). PCBA contains PCB and all necessary electronic components, which work together to realize the preset functions of the circuit board.

‌Function and application‌:

The main function of PCB is to support and connect electronic components, while PCBA integrates electronic components into a complete circuit system, which can be used in the manufacture of various electronic products.

PCBA is the core part of electronic products and directly determines the performance and function of the product.

‌Manufacturing process‌:

The manufacturing process of PCB includes circuit design, PCB board design, PCB template production, copper foil etching, drilling, tin spraying and board making.

The production of PCBA requires component mounting, welding, testing and other processes.

In summary, the main difference between PCB and PCBA lies in their definition, function, application and manufacturing process. PCB is a basic electronic component, mainly used to support and connect electronic components, while PCBA is a finished product formed by welding electronic components to PCB. It has specific circuit functions and is an indispensable part of electronic products.

What is the difference between PCB manufacturing and assembly?

The main difference between PCB manufacturing and assembly is that they involve different processes and focuses. ‌

‌PCB manufacturing‌ mainly involves the process of converting raw materials into printed circuit boards through a series of process flows, including design, layout, etching, lamination, drilling, welding and other steps, and finally forming a complete and usable printed circuit board.

‌PCB assembly‌ is the process of soldering electronic components to the printed circuit board according to the design requirements after the PCB is manufactured. The focus of assembly is to ensure that all components are in the correct position and direction, the pins of each component are fully soldered to the designated pads, and there is no excess solder or other excess materials to ensure the normal operation and reliability of the circuit board.

In short, ‌manufacturing‌ covers the entire production process from raw materials to finished products, including design, production and testing, while ‌assembly‌ is a link in the manufacturing process that focuses on accurately mounting electronic components on printed circuit boards to ensure the final function and performance of the product.

Conclusion:

PCB assembly is an important part of manufacturing and affects the quality of the final product. Therefore, choosing the right manufacturer becomes particularly important. BEST Technology is committed to becoming the world’s most trusted one-stop electronic circuit solution provider, while focusing on PCBA prototyping and small batch production. Choosing us will get the best quality products.

Is PCB design hard to learn?

PCB design is not difficult to learn. The key lies in mastering the relevant basic knowledge and practical experience.

PCB design mainly involves electronic circuit knowledge and software operation skills. For people with electronic circuit foundation, it is relatively easy to learn the use of PCB design software. It is important that learners should use their spare time to learn and practice at the same time. They can assist in learning by watching video tutorials. These resources can help understand the basic concepts and skills of circuit design and software operation.

In addition, the difficulty of PCB design lies mainly in the design of wiring rules, which is the most complex and critical part of PCB design. Beginners should pay attention to the design of conventional constraint rules, such as the size of vias, line width and line spacing, etc., which need to be mastered through practical operation and practice. Just reading materials is not enough. Practical operation and practice are the key to improving PCB design capabilities.

In general, although PCB design involves certain technical difficulties, it can be gradually mastered through systematic learning and practice.

What should I learn before PCB design?

Before PCB design, you need to learn the following key knowledge and skills:

1. Basic knowledge reserve: First of all, you need to understand various electronic components, such as resistors, capacitors, inductors, diodes, triodes, integrated circuits, etc. You also need to be familiar with common circuit topologies, such as amplifier circuits, filter circuits, oscillation circuits, and their functions and representation methods in circuits.

2. PCB design software: Be proficient in at least one PCB design software for schematic design, component layout, wiring, and generation of PCB production files, such as Altium Designer, EAGLE, PADS, OrCAD, etc.

3. Circuit board manufacturing process: Understand the manufacturing process of PCB circuit boards, including substrate material selection, circuit pattern transfer, etching, drilling, welding, assembly, etc.

4. Component packaging: Familiar with the packaging types and sizes of various components, such as DIP, SOP, QFP, BGA, etc., as well as their characteristics and usage scenarios.

5. Basic terms and concepts: Master some basic PCB terms, such as microstrip, stripline, differential line, via, solder mask, silk screen, structural diagram, etc.

6. Circuit function and signal flow: Understand the function and signal flow of the circuit, and be able to distinguish between digital circuits and analog circuits, as well as places with large and small currents.

By mastering the above knowledge and skills, you can better design and layout circuits, improve the performance and reliability of circuit boards,

Which software is used for PCB design?

1. Altium Designer is a powerful PCB design software that provides a wealth of tools and libraries to quickly create complex circuit board designs. This software has an intuitive interface and powerful simulation functions to help designers quickly verify the correctness of the design. It also supports multiple design file formats, which is convenient for collaboration with other design tools.

2. Cadence Allegro is a comprehensive circuit board design software with powerful layout and routing tools, as well as multiple simulation and verification tools to ensure the correctness of the design. It also supports multiple design file formats for team collaboration.

3. Mentor Graphics DesignX is also a powerful PCB design software that provides a variety of tools and libraries to help designers quickly create complex circuit board designs. It also has an intuitive interface and powerful simulation functions, and supports multiple design file formats.

4. PADS is a professional circuit board design software with powerful layout, routing, simulation and verification functions, which can quickly complete complex PCB design work. It also supports multiple design file formats, which is convenient for collaboration with other design tools.

These software are all commonly used PCB design tools with powerful layout, routing, simulation and verification functions, which can help designers quickly complete complex PCB design work.

What is the basic rule of PCB design?

The basic rules of PCB design involve many aspects, including layout, routing, power and ground design, signal integrity, etc.

1. Layout design:

Follow the design principle of placing in a straight line along the signal flow direction to avoid the signal from circling back and forth to reduce the impact of direct signal coupling.

The filtering, protection and isolation devices of the interface circuit should be placed close to the interface to achieve effective protection, filtering and isolation effects.

For high-speed signals or high-current signals, multi-layer board design should be considered to control the signal loop area.

2. Wiring rules:

Control the length of the trace, especially for important signal lines, such as clock signals, the trace length should be shortened as much as possible to reduce unnecessary interference.

Avoid forming self-loop traces to reduce radiation interference.

Follow the principle of minimum ground loop, design the signal line and its loop to form the smallest possible loop area to reduce external radiation and external interference.

3. Power and ground design:

The power plane should be retracted a certain distance relative to its return ground plane to effectively suppress edge radiation problems.

Avoid overlapping of different power layers in space to reduce interference between different power supplies.

4. Drawing:

When drawing the board frame, a specific line width should be used to ensure that the error between the board frame size and the assembly size is within the allowable range.

Set a reasonable origin to ensure that the coordinates of the SMT original are within the first quadrant.

Set a prohibited area, especially prohibiting routing and placing components within a certain range around the mounting hole.

Following these basic rules can ensure the effectiveness and reliability of PCB design, while improving product performance and user experience.

How long does it take to design a PCB board?

It takes about 1-2 days to design a PCB board, and the specific time depends on multiple factors, including the number of layers of the PCB, design complexity, etc.

‌Number of layers and complexity‌: The more layers the PCB has, the more complicated the design process is, and more time and delicate work are required to ensure the correctness and performance of the circuit.

‌Design stage‌: PCB design includes multiple steps such as design layout, schematic drawing, and PCB design conversion.

The time to design a PCB board is a comprehensive estimate involving multiple stages and factors.

What is the proper PCB layout?

Proper PCB layout involves many aspects, including structural requirements, heat dissipation considerations, component spacing, routing rules, etc. ‌

‌Structural requirements‌: First, the PCB layout must meet the structural requirements, including the location arrangement of structural components such as power sockets and DVI interfaces.

‌Heat dissipation considerations‌: The distribution of heat sinks should be even to ensure good ventilation of the air path. Avoid heat sinks blocking the air path to avoid affecting the heat dissipation effect‌.

‌Component spacing‌: Capacitors, ICs, etc. should be kept away from thermal components to avoid being affected by heat.

‌Routing rules‌: The design of the current loop should consider the convenience of threading, and the lead hole spacing should not be too far or too close. The layout of input/output and AC/socket should meet the consistency of the length of the two lines, leaving a certain space margin, and pay attention to the position of the plug wire buckle and the convenience of plugging and unplugging‌.

‌Special component layout‌: For high-frequency components and components with high potential difference, the distance between them should be increased to avoid electrical interference and damage.

Wiring design parameters‌: including the line width of the copper trace, the minimum gap between the copper foil traces, the minimum distance between the copper foil traces and the edge of the PCB board, etc. ‌ .

In summary, the correct PCB layout is a process that comprehensively considers the structure, heat dissipation, component spacing, routing rules and wiring design parameters, aiming to optimize the performance and reliability of the circuit board.

Conclusion:

Designing a PCB board is a complex and meticulous process involving multiple steps and considerations. Systematically complete the design process of a PCB board. Each step requires careful operation and multiple checks to ensure the quality and reliability of the final product. ‌ BEST Technology’s PCB designers have many years of design experience and are far ahead in the industry design. We can meet any PCB design you need.

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