Archive for the ‘FR4 PCB’ Category

Wi-Fi Module PCBA Design | Box Build Assembly Manufacturer

Tuesday, October 22nd, 2024

Wireless technology has transformed the way devices communicate. At the heart of this transformation are Wi-Fi modules. These small components power a wide range of applications, from home automation to industrial systems. In this blog, we’ll explore the functions of Wi-Fi modules, their uses, design considerations in PCB assembly and their differences from Bluetooth.

What is a Wi-Fi Module?

The Wi-Fi module, also known as the wireless module, belongs to the transmission layer of the Internet of Things (loT). It integrates a processor, memory, transceiver, and sometimes an antenna. A Wi-Fi module is to convert the serial port or TTL level into an embedded module that meets the Wi-Fi wireless network communication standards, with built-in wireless network protocol IEEE802.11b.g.n protocol stack and TCP/IP protocol stack.

Wi-Fi Module PCBA Design | Box Build Assembly Manufacturer

The module handles the task of connecting a device to a wireless router, allowing it to send and receive data over the internet. If embedded a Wi-Fi module in traditional hardware devices, then we can directly use Wi-Fi to connect to the Internet. It can be said, it is an important part of wireless smart home, M2M and other IoT applications.

Types of Wi-Fi Module

According to the different functions, Wi-Fi modules can be divided into three categories:

1. General Wi-Fi modules

Such as USB or SDIO interface modules on our mobile phones, laptops and tablets. Wi-Fi protocol stack and driver are run in Android, Windows and IOS systems, which require a very powerful CPU to complete the application.

2. Router Wi-Fi module

The most typical one is our home router, its protocol and driver has powerful Flash and Ram resources chip plus Linux operating system.

3. Embedded Wi-Fi module

Such as 32-bit MCU, built-in Wi-Fi driver and protocol, interface for the general MCU interface such as UART. Suitable for all kinds of smart home or smart hardware items.

What is the Difference Between Wi-Fi and Bluetooth Modules?

While both Wi-Fi and Bluetooth modules enable wireless communication, their usage and performance differ significantly:

1. Frequency

The frequency of Wi-Fi has 2.4G and 5G bands. Wi-Fi 2.4G band has 13 channels, 2401~2423MHz. Wi-Fi 5G frequency band is divided into 5.2G band and 5.8G band, and the 5.8G frequency band is: 149, 153, 157, 161, 165; The 5.2G band must support 11ac, and the available channels are 36, 40, 44, 48, 52, 56, 60, and 64. Under normal circumstances, it is recommended to avoid 52, 56, 60, 64 channels, because they conflict with radar channels;

Bluetooth only has 2.4G band: 2.402GHz ~ 2480GHz, a typical Bluetooth has 76 channels, each channel is 1MHz. And bluetooth BLE has 40 channels, each channel 2MHz, of which 37 channels belong to the data channel, 3 channels belong to the broadcast channel;

2. Application

Wi-Fi can directly access the network, and Bluetooth needs conversion processing. Therefore, WiFi is more suitable for 1-to-many local area networking, such as home and company Internet access environment. Compared with Wi-Fi module, bluetooth is more suitable for short-range and high-stability transmission, such as smart headphones. Additionally, bluetooth mesh networking is especially suitable for smart home wireless control and other applications.

3. Transmission Distance

The transmission distance of Wi-Fi is further than that of Bluetooth, which can reach several hundred meters, while the transmission distance of Bluetooth is generally within 100 meters;

4. Transmission Rate

Wi-Fi: 54Mbps; Bluetooth: 2Mbps;

Wi-Fi is more suitable for big data transmission.

5. Speed

Wi-Fi is generally faster than Bluetooth. It can handle large file transfers or streaming content without any issues. Bluetooth is slower but works well for smaller data transfers like audio streaming or simple file sharing.

What is the Range of a Wi-Fi Module?

‌The coverage range of the WiFi module usually depends on the specific application scenario and environmental conditions. According to the IEEE 802.11 standard, the maximum distance that wireless devices can cover is usually 300 meters, but this depends on the environment is open or not.

In the specific environment, the coverage of the WiFi module will be affected by a variety of factors. For example, in an ideal environment of accessibility and interference, the wireless transmission distance of a wireless router is 100 meters indoors and 300 meters at outdoors. In the actual home environment, the wireless signal will be attenuated when passing through obstacles such as walls, glass, doors, and furniture, affecting the transmission distance. If an external antenna is used, the transmission distance can reach 30 ~ 50 km or even more, depending on the gain of the antenna itself.

Advantages of Wi-Fi Module

1. Wide coverage

WiFi module supports ‌IEEE 802.11b/g/n and other standards to provide a wide range of wireless coverage, suitable for a variety of indoor and outdoor environments.

2. High-speed transmission

WiFi module supports a high data transmission rate, which can meet the requirements of high-speed data transmission, and is suitable for application scenarios with a large amount of data.

3. Compatibility and ecosystem

WiFi module supports a variety of communication protocols, such as ‌Wi-Fi, ‌Bluetooth, etc., has good compatibility and ecosystem, and can be integrated with a variety of devices and services.

4. Easy to install and use

WiFi modules are usually plug and play, easy to install and use, suitable for a variety of devices and system integration.

Disadvantages of a Wi-Fi Module

1. Power consumption

One downside of Wi-Fi modules is their higher power usage compared to other wireless technologies, such as Bluetooth. This can be a concern for devices running on battery power.

2. Interference

Wi-Fi operates on the same frequencies as other devices, such as microwaves and cordless phones.

3. Security

Since Wi-Fi networks are widespread, they can be vulnerable to hacking. Proper security measures, such as encryption, must be implemented to protect data.

What is a Wi-Fi Module Used For?

Wi-Fi modules have a wide range of applications across industries. Actually, it exist everywhere need networks. It can be said, it can be used in every fields. Here are some typical applications:

Smart Homes

Wi-Fi modules power smart devices like security cameras, thermostats, and lighting systems. They connect to a home Wi-Fi network, so users to control them remotely through apps.

Industrial Equipment

In manufacturing or logistics, Wi-Fi modules enable machines to communicate wirelessly.

Consumer Electronics

Devices like laptops, gaming consoles, and smart TVs rely on Wi-Fi modules for wireless internet access.

Healthcare Devices

Medical equipment, such as patient monitors or wearable devices, often use Wi-Fi modules to transmit data to a healthcare provider in real time.

IoT Devices

The IoT relies heavily on Wi-Fi modules. Devices ranging from smart refrigerators to connected doorbells use Wi-Fi to communicate with each other and with cloud-based systems.

Wi-Fi Module Price

Wi-Fi modules are available at various price points, depending on their features and intended use. For instance, the ESP8266 typically costs between $2 to $5. The ESP32, with its additional capabilities, is priced slightly higher, ranging from $5 to $10. High-end industrial Wi-Fi modules can be more expensive, ranging from $20 to $50.

The price may also vary depending on factors like antenna design, supported protocols, and whether the module is designed for mass production or individual projects.

What is the Most Common Wi-Fi Module?

The ESP8266 is one of the most popular and widely used Wi-Fi modules. It is favored in many IoT applications due to its low cost, ease of use, and compact size. Another frequently used module is the ESP32, which offers additional features such as dual-core processing, built-in Bluetooth. In addition to them, there are some other common Wi-Fi module that used in the electronics.

Wi-Fi Module	Description	Frequency Brand	Range	Price	Special Features
ESP8266	Popular for IoT applications due to low cost and ease of use.	2.4 GHz	Up to 150 feet	$2 – $5	Compact size, low power, integrated TCP/IP protocol stack.
ESP32	Offers better performance with dual-core and built-in Bluetooth.	2.4 GHz, Bluetooth	Up to 300 feet	$5 – $10	Dual-core processing, Bluetooth, multiple I/O options.
CC3200	A Texas Instruments Wi-Fi module designed for IoT and smart products.	2.4 GHz	Up to 200 feet	$8 – $15	Built-in ARM Cortex-M4 processor, low power, encryption features.
RN171	A high-performance Wi-Fi module from Microchip.	2.4 GHz	Up to 330 feet	$20 – $30	Embedded TCP/IP stack, simple serial interface.
ATWINC1500	A low-power module designed for IoT and wearable devices.	2.4 GHz	Up to 200 feet	$7 – $15	Ultra-low power, integrated network stack, supports power-saving modes.
WizFi210	A stable Wi-Fi module designed for industrial applications.	2.4 GHz	Up to 300 feet	$10 – $25	Low power, fast boot-up, secure connection.
Roving Networks RN131	Suitable for long-range industrial and commercial applications.	2.4 GHz	Up to 400 feet	$25 – $40	High-performance, robust design, supports SSL encryption.

Considerations in PCBA Design with a Wi-Fi Module

When integrating a Wi-Fi module into PCBA design, several factors need to be considered to ensure optimal performance:

Antenna Design and Placement

A key factor in wireless performance is the placement of the antenna. Ensuring there are no obstructions near the antenna can significantly improve signal strength. The module should be positioned to minimize interference from nearby components.

Power Supply

Wi-Fi modules require a stable and sufficient power supply to function effectively. Voltage fluctuations or insufficient power can result in poor connectivity or even module failure.

Thermal Management

Wi-Fi modules can generate heat, especially during heavy use. Proper heat dissipation methods, such as using heat sinks or thermal vias, should be incorporated into the PCBA design to maintain optimal performance.

EMI and EMC Compliance

Wireless communication devices must adhere to electromagnetic interference (EMI) and electromagnetic compatibility (EMC) standards. Proper shielding and circuit design can help reduce interference and improve reliability.

Firmware Integration

Many Wi-Fi modules come with firmware that handles wireless communication tasks.

One-Stop Box-Build Assembly for Wireless Communication Devices

For companies looking to develop wireless communication devices, Best Technology is your go-to choice. We offer one-stop PCBA and box-build service that can handle everything from component sourcing and PCBA design to final product assembly. By partnering with us, you can reduce much development time, and get a high quality, fast delivery, low cost PCBA with Wi-Fi modules.

With over 18 years of experience in printed circuit boards and as one of the leading PCB manufacturers, we support over 2,000 customers in different industrial areas worldwide. You can count on a PCB board manufacturer like us to meet your one-stop electronics manufacturing demands. We have an experienced engineer, production and quality team to fully understand the unique requirements of your industry, such as the particular acceptance criteria in medical, automotive, communication and aerospace industries. Contact us right now to get your PCB quotation!

Tags:bluetooth module, Wifi module, wifi module pcb
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What is a high temperature resistance flexible PCB?

Tuesday, October 22nd, 2024

A high temperature resistant flexible PCB is a flexible printed circuit board that can maintain stable performance in a high temperature environment. It is usually composed of a flexible substrate, a conductive layer, and a cover layer. It has the characteristics of being bendable, foldable, and lightweight, and can withstand high temperatures without affecting its electrical and mechanical properties.

What is the maximum temperature for a flex PCB?

The high temperature resistance of a flexible PCB mainly depends on its substrate material. Generally speaking, the maximum temperature that a flexible PCB can withstand can reach 280 degrees in a short period of time, but the long-term temperature is generally between 120 degrees and 150 degrees. ‌

What is a high temperature resistance flexible PCB?

Different types of flexible PCB materials have different tolerances to temperature. PI is a commonly used flexible PCB substrate material that has excellent heat resistance and stability. It can maintain performance in the range of -200 degrees to 300 degrees, but the long-term use temperature is generally between 120 degrees and 150 degrees. ‌

In addition, the glass transition point of solder mask is about 110 degrees, so special attention should be paid to the temperature limit of these materials when designing flexible PCBs. ‌

What temperature should flexible PCB soldering be?

‌The optimal temperature range for flexible PCB soldering is 290-310 degrees Celsius. This temperature range is suitable for most flexible PCB soldering operations and can ensure soldering quality and component reliability.

In specific operations, the soldering time should be kept within a few seconds to prevent damage to the pads of the PCB board. Accurate temperature management is essential to ensure the solder joint quality and circuit performance of the PCB board. The soldering temperature may vary for different types of flexible PCBs.

What is high Tg PCB?

‌High Tg PCB refers to PCB materials with higher glass transition temperature (Tg). ‌ Tg is the temperature point at which the material changes from glass to rubber state. High Tg materials can still maintain good mechanical strength and dimensional stability at high temperatures. ‌

The main advantages of high Tg PCB include:

‌Heat resistance‌: High Tg materials can still maintain good mechanical strength and dimensional stability at higher temperatures and are suitable for high temperature environments. ‌

‌Moisture resistance‌: High Tg materials have low moisture absorption. Even after being heated after moisture absorption, they can maintain good mechanical strength and adhesion, reducing the risk of failure caused by moisture‌.

‌Chemical resistance‌: High Tg materials have better chemical stability at high temperatures and are not easy to decompose‌.

‌Dimensional stability‌: When the temperature changes, the dimensional changes of high Tg materials are small, ensuring the accuracy of PCB‌.

Application scenarios of high Tg PCB include:

Lead-free manufacturing process‌: In highly functional and multi-layered electronic products, high Tg materials can ensure the stability and reliability of PCB in lead-free processes‌.

‌High temperature environment‌: In applications that need to withstand high temperature environments, such as computers, mobile communication devices, etc., high Tg PCBs can ensure stable operation of the equipment‌.

What are the disadvantages of flexible PCB?

The main disadvantages of flexible PCB include:

‌High one-time initial cost‌: Since flexible PCBs are designed and manufactured for special applications, the initial circuit design, wiring and photographic plate costs are high.

‌Difficult to change and repair‌: Once a flexible PCB is made, it must be changed from the base map or the compiled photolithography program, so it is not easy to change. Its surface is covered with a protective film, which must be removed before repair and restored after repair, which is a more difficult task‌.

How thick is the copper in a flex PCB?

The copper foil thickness in a flexible PCB is usually around 0.1mm. The copper foil thickness of a flexible PCB is generally 0.1mm, which is one of its common specifications‌.

In addition, the copper foil thickness of a rigid PCB has a wide range, and common thicknesses include 0.2mm, 0.4mm, 0.6mm, 0.8mm, 1.0mm, 1.2mm, 1.6mm, 2.0mm, etc.‌. The copper foil thickness of a rigid PCB can be adjusted according to demand. For example, in an environment where high current and high power are required, the copper foil thickness may be higher‌.

Flexible PCB materials usually include polyester film, polyimide film, and fluorinated ethylene propylene film, etc. These materials are widely used in curved and flexible circuit designs in electronic devices‌.

Why are Flex PCBs so expensive?

First, material cost is one of the main factors affecting the price of flexible PCBs. Flexible PCBs mainly use special materials such as polyimide (PI) and polyester film, which have excellent heat resistance and electrical properties, but are more expensive.

Second, manufacturing process is also an important reason for the high cost of flexible PCBs. The production process of flexible PCBs includes multiple complex links such as exposure, development, etching, lamination and testing. High-precision manufacturing processes, such as fine line etching and precise alignment, require advanced equipment and technology, which increases production costs.

Design complexity is also a key factor. The design and manufacture of flexible PCBs involve multiple processes, such as etching, copper plating, drilling, etc. The higher the complexity of the process, the higher the manufacturing cost.

Finally, market demand also affects the cost of flexible PCBs. Mass production can effectively reduce unit costs, while small batch or customized production may lead to higher costs.

What is rigid-flex PCB vs flex PCB?

The main difference between rigid-flex PCB and flexible PCB lies in their structure and application scenarios. Rigid-flex PCB combines the characteristics of rigid PCB and flexible PCB, while flexible PCB is made entirely of flexible materials.

Rigid-flex PCB is a circuit board that combines rigid board and flexible board, and is usually used in areas where both rigidity and flexibility are required. This type of circuit board uses flexible materials in specific areas and remains rigid in other areas to meet complex design requirements.

Flexible PCB is made entirely of flexible materials and is usually used in applications that require high flexibility and space saving. Flexible PCB uses flexible materials such as polyimide, allowing the circuit board to be easily bent and folded in a small space. This type of PCB is widely used in modern smart devices such as smartphones, tablets and wearable devices to achieve smaller size and more complex functions.

What is the difference between FR4 and flex PCB?

The main difference between FR4 and flexible PCB lies in their materials, structure and application scenarios. FR4 is a rigid PCB substrate, mainly composed of glass fiber and epoxy resin, with good electrical properties and mechanical strength, suitable for applications requiring high stability and reliability. Flexible PCBs are highly flexible and bendable, suitable for applications with limited space or frequent bending.

FR4 features and applications:

FR4 is currently the most common PCB substrate. FR4 has good electrical properties, with a dielectric constant between 4.5 and 4.8, suitable for medium and low frequency applications; in terms of thermal performance, its thermal expansion coefficient is about 14-17ppm/°C, and its heat resistance can reach 260°C; in terms of mechanical properties, FR4 has high bending strength and tensile strength, suitable for manufacturing processes such as drilling, etching, and copper plating.

Due to its stability and reliability, FR4 is often used in applications such as display screens and reverse cam screens that require high stability.

Flexible PCBs features and applications:

Flexible PCBs (FPCs) are mainly made of materials such as polyimide and are highly flexible and bendable. They are often used in applications with limited size or frequent bending.

The design of flexible PCB is relatively simple, but when rigidity needs to be increased for easy installation or assembly, reinforcement plates such as PI, FR-4 or steel sheets are used.

Due to the high flexibility of flexible PCBs, they are often used in devices that require frequent movement or deformation, such as touch sensors and automotive lighting systems.

As a new type of PCB in the electronics field, high-temperature resistant flexible PCBs have gradually become a popular choice in the electronics field with their excellent high-temperature resistance, bendability, foldability, light weight, stable electrical performance, and good mechanical properties. High-temperature resistant flexible PCBs play an important role in applications in high-temperature environments such as aerospace, automotive electronics, industrial control, and medical equipment.

Tags:fpc, PCB, tg
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6 Layer PCB Stackup, Thickness, Impedance Control

Friday, October 18th, 2024

What is a 6 Layer PCB?

A 6 layer PCB is a printed circuit board that has six conductive layers. It consists of 4 inner layers and 2 outer layers, of which the inner layer is made of copper foil and located in the center of the board (we cannot see it by our eyes), while the outer layer is located on the top and bottom of the board. This design packs a punch, letting you fit more complex circuitry into a smaller space. It’s perfect for small electronic devices that need to do a lot.

6 Layer PCB Stackup, Thickness, Impedance Control

6 Layer PCB Structure

In a typical 6 layer PCB stackup, the conductive layers are numbered from top to bottom, starting with Layer 1. Here’s what a standard configuration looks like:

Layer 1: Top Layer
Layer 2: Reference Plane 1
Layer 3: Signal or Plane Layer 2
Layer 4: Signal or Plane Layer 3
Layer 5: Reference Plane 2
Layer 6: Bottom Layer

The top and bottom layers are the two most common layers in a 6-layer PCB. They are often used to mount large components and connectors. The main role of the top and bottom layer is to provide the structure and support of the circuit board, and can also be used to connect external devices. The middle layers handle signals and reference planes (like ground and power).

Common 6 Layer PCB Stack-Up

When it comes to stacking up those layers, you have a few common configurations:

Stack-Up Option 1: S G S S P S

Top Layer (Signal)
Layer 2 (Ground)
Layer 3 (Signal)
Layer 4 (Signal)
Layer 5 (Power)
Bottom Layer (Signal)

This kind of stack up has more signal layers, which is conducive to the wiring work between components; Because POWER and GND are far apart and not tightly coupled, the signal layers are directly adjacent, which is easy to cause crosstalk. Therefore, staggered wiring is required during wiring. When the power supply impedance is low.

Stack-Up Option 2: S S G P S S

1. Top Layer (Signal)
2. Layer 2 (Signal)
3. Layer 3 (Ground)
4. Layer 4 (Power)
5. Layer 5 (Signal)
6. Bottom Layer (Signal)

POWER and GND are tightly coupled, but the plane reference is too far away and the signal isolation is not good, which is easy to cause crosstalk.

Stack-Up Option 3: S G S G P S (preferred solution)

1. Top Layer (Signal)
2. Layer 2 (Ground)
3. Layer 3 (Signal)
4. Layer 4 (Ground)
5. Layer 5 (Power)
6. Bottom Layer (Signal)

POWER and GND layers are tightly coupled, with good EMI characteristics, and the signal layer is directly adjacent to the internal electrical layer, and is effectively isolated from other signal layers, which is not easy to crosstalk.

Stack-Up Option 4: S G S P G S

1. Top Layer (Signal)
2. Layer 2 (Ground)
3. Layer 3 (Signal)
4. Layer 4 (Power)
5. Layer 5 (Ground)
6. Bottom Layer (Signal)

POWER and GND are tightly coupled. The signal layer is adjacent to the ground layer, the power layer is paired with the ground layer, the impedance of each line layer can be better controlled, and the magnetic field line can be well absorbed by both layers. This layered scheme is suitable for the design of high chip density and high clock frequency.

6 Layer PCB Thickness

The total thickness of a 6 layer PCB usually ranges from 0.8 mm to 2.0 mm. Of course, this can vary based on materials and what you’re aiming for. Each layer contributes to this thickness, and the copper thickness often ranges from 1 oz to 3 oz. Thicker boards tend to offer better durability and heat dissipation, but they can also be less flexible, which is something to consider depending on your application. The common thickness structure are showing as below:

Above are the common structure and thickness of a 6 layer multi-layer PCB, if you want thicker thickness, welcome to contact with us, our expertise team will give you the best and cost-effective solution!

6 Layer PCB Manufacturing Process

6 Layer PCB Price

The price of a 6 layer PCB doesn’t have a standard number/value. It varies based on factors like material, size, and complexity. Generally, they are more expensive than simpler designs due to the increased number of layers and the advanced manufacturing processes involved. However, the investment often leads to improved performance and durability. Here are some factors that will effect your 6 layer PCB price:

Design complexity: If the design is intricate, expect a higher price.
Material quality: Premium materials can drive up the cost but often improve performance.
Volume: Producing in bulk usually lowers the cost per unit.
Manufacturing process: The more difficult process, it will cost much more. Like a normal 6 layer FR4 PCB with through holes is cheaper than 6layer HDI PCB with blind or buried via holes.
Surface treatment: Different treatment you choose will affect your overall price.

In general, you’re looking at prices that range from $5 to $50 or more per unit. It might sound steep, but investing in a quality 6 layer PCB can really pay off in terms of performance and reliability.

6 Layer PCB vs. 4 Layer PCB

6 layer PCB is different with 4 layer PCB, from the board thickness, cost, line width and spacing and etc. Here we listing three main differences between them:

1. Board thickness

The thickness of the PCB board is the thickness of the fingerboard, usually in millimeters. There is a difference in thickness between six-layer and four-layer plates. The thickness of the six-layer plate is usually between 1.6mm and 2.0mm, while the thickness of the four-layer plate is between 1.0mm and 1.6mm. Therefore, the thickness of the six-layer plate is thicker than that of the four-layer plate.

2. Line width

The line width refers to the width of the wire on the circuit board. There is also a difference in line width between six-ply and four-ply panels. The line width of a six-layer board is wider than that of a four-layer board. This is because in a six-layer board, there are more circuit layers, so it is easier to accommodate a wider line width.

3. Drilling

Drilling is an indispensable part of the PCB board production process. It is usually used to punch holes in the board so that electronic components can be installed. There is also a difference in the number of holes drilled between six-ply and four-ply panels. Because the six-layer board has more circuit layers, the number of holes is relatively high.

Impedance Control for 6 Layer PCB

‌The impedance control of 6-layer PCB is to control the impedance value of signal transmission by designing the geometry and material of the circuit board to improve the speed and quality of signal transmission, and reduce signal reflection and interference. ‌ Common methods of controlling impedance include adjusting parameters such as the width, spacing and thickness of the signal lines, using differential lines to reduce signal interference and noise, and using interlayer isolation to prevent signal interference.

In the 6-layer PCB design, the specific implementation methods of impedance control include:

Signal line width and spacing control

Signal line width and spacing is a key factor affecting the impedance. Strictly control the line width tolerance within ±10%, and pay attention to the possible pinholes, notches, dents and other problems on the wire, which will further affect the line width and impedance.

Dielectric layer thickness control

Dielectric layer thickness has a significant effect on impedance. Use advanced manufacturing technology and equipment to ensure the uniformity and consistency of the thickness of the medium layer, and strictly control the thickness tolerance of the medium layer within the design requirements.

‌The use of differential line

Differential line can effectively reduce signal interference and noise, improve the quality of signal transmission and anti-interference ability.

Partially filled with copper and grounded

Fill the area without components or wires with copper, and ensure that the copper filled area is connected to the internal ground layer or power layer at multiple points. The distance between the connection holes does not exceed 1/20 of the highest harmonic wavelength of the signal ‌

6 Layer PCB Design Considerations

When you’re designing a 6 layer PCB, there are several things to keep in mind:

Reference Plane Placement

For the best performance, reference planes (usually ground and power) should be placed next to the routing layers. This setup helps maintain controlled impedance, which is critical for high-speed designs. Having a continuous ground plane right next to signal layers is a great practice.

Plane Splits

Sometimes, reference planes need to be divided into separate sections for analog and digital power. This keeps the analog circuitry isolated from the digital side, which helps reduce noise in sensitive areas.

Symmetry in Design

It’s usually best to keep the stackup symmetrical, with reference planes both above and below the signal layers. This arrangement improves signal integrity. But in some cases, asymmetrical designs are used depending on specific design needs.

Thermal Management

Consider how to manage heat, especially in high-power scenarios, to ensure reliability.

Signal Routing

High-speed or noise-sensitive signals should be routed on the inner layers between reference planes. Keeping these signals away from the outer layers helps minimize interference.

Breakout Vias

When transitioning from inner layers to outer layers, breakout or stub vias should be used. These vias help manage any stub effects, keeping things tidy and controlled.

Minimum Spacing

Lastly, always follow the board fabricator’s guidelines for minimum trace width, spacing, and annular ring sizes. This ensures the board meets the necessary standards and avoids any manufacturing issues.

Simulation Tools

Use simulation software to identify potential issues before manufacturing, which can save you time and hassle.

Best Technology is a reliable PCB manufacturer in China. As one of the highly experienced circuit board suppliers, our products and services include a wide range of printed circuit boards such as rigid PCBs, flex PCBs, rigid-flex PCBs, aluminum PCBs, RF Microwave PCBs, high-speed PCBs, high-frequency PCBs, HDI PCBs, etc. If you have such demands, welcome to contact us.

Tags:6 layer pcb, 6 layer pcb thickness, 6 layerpcb
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Rogers RT Duroid 5880 | High Frequency Rogers RO5880 PCB Manufacturer

Wednesday, October 16th, 2024

What substrate is Rogers RT Duroid 5880?

Rogers RT Duroid 5880 is a high-frequency laminate specifically designed for applications where precision and low signal loss are critical. The substrate is a composite material known for its excellent performance in RF and microwave circuits. It uses a PTFE (polytetrafluoroethylene) base reinforced with glass microfibers.

The use of glass microfiber ensures the material is durable but lightweight, making it suitable for applications in which weight is a factor. Its composition is perfect for projects where high-frequency signals are involved. From defense systems to automotive radar, RT Duroid 5880 is a reliable choice. It has become the go-to substrate for engineers and designers looking for efficiency, precision, and durability.

Rogers RT Duroid 5880 | High Frequency Rogers RO5880 PCB Manufacturer

Composition of Rogers RT/duroid 5880

RT Duroid 5880 is composed of PTFE (polytetrafluoroethylene) combined with glass microfiber. PTFE provides a low dissipation factor, which reduces signal loss. This is important for maintaining high performance in RF and microwave applications. Glass microfiber reinforces the material, make it stronger without adding unnecessary weight. The composition also includes copper cladding, which is typically laminated on both sides. The copper layer helps with conductivity, ensuring signals travel efficiently across the board.

The unique combination of PTFE and glass microfiber gives RT Duroid 5880 its excellent mechanical stability. It also minimizes the effect of temperature changes, which is critical for high-frequency circuits. As a result, the material can handle extreme temperatures without affecting the performance of the PCB.

RT/duroid 5880 Specifications

The following table highlights the important specifications of Rogers RT Duroid 5880. These specs reflect the high performance of RT Duroid 5880 for complex RF and microwave tasks.

Property	Value
Dielectric Constant (Dk)	2.20 (±0.02)
Dissipation Factor (Df)	0.0004 (measured at 10 GHz)
Thermal Conductivity	0.20 W/m/K
Operating Temperature Range	-55°C to +150°C
Water Absorption	0.02%
Volume Resistivity	1.7 x 10^9 MΩ·cm (minimum)
Surface Resistivity	1.4 x 10^8 MΩ (minimum)
Coefficient of Thermal Expansion (CTE)	46 ppm/°C (in X-Y axis)
Tensile Strength	10.3 MPa
Flammability	UL 94 V-0
Peel Strength	5.0 N/mm (after soldering)

RT/duroid 5880 Thickness

RT Duroid 5880 comes in various thicknesses. Engineers can choose the right thickness depending on their project’s needs. Rogers RT/duroid 5880 laminate is commercially available in sheet stock and roll stock forms in a range of thicknesses. Here’s a list of the standard thicknesses available:

Available sheet sizes:

304.8 x 457.2 mm
457.2 x 609.6 mm
609.6 x 914.4 mm

Standard thickness:

0.127 mm (5 mils)
0.254 mm (10 mils)
0.381 mm (15 mils)
0.508 mm (20 mils)
0.787 mm (31 mils)
1.524 mm (60 mils)
3.175 mm (125 mils)

Available roll widths:

304.8 mm
609.6 mm
1219.2 mm
Standard roll length: 76.2 meters
Thickness range: 0.127 mm to 1.575 mm

RO5880 RF PCB Advantages

Rogers RT Duroid 5880 has a lot of strengths when used in RF and microwave PCB projects:

Minimal Signal Loss

With a low dissipation factor of 0.0004, it reduces signal loss, which is very helpful for high-frequency systems like radar or satellite communications.

Strong Stability

It holds up well under temperature changes and in humid environments, keeping circuits running smoothly even in tough conditions.

Reliable Electrical Properties

The dielectric constant of 2.20 remains stable over a range of frequencies. This helps keep circuits working consistently without interference or signal issues.

Heat Tolerance

It withstands heat up to 150°C, making it a good choice for systems that need to handle higher temperatures.

Low Moisture Absorption

With only 0.02% water absorption, the material works well in damp environments. Outdoor systems like antennas benefit from this.

Ease of Manufacturing

The material is easy to work with during production, which keeps costs lower and speeds up manufacturing.

Chemical Resistance

The PTFE base resists damage from chemicals and solvents, making the material last longer in harsh environments like aerospace and industrial applications.

Typical Applications of High-Frequency PCB

High-frequency PCBs built with Rogers RT Duroid 5880 serve important roles across many industries:

Aerospace – used in radar, satellite, and navigation systems, RT Duroid 5880 supports reliable communication and tracking, even in high-pressure environments.

Telecommunications – in mobile networks, base stations, and antennas, high-frequency PCBs help maintain clear and fast data transmission, supporting the backbone of communication systems.

Medical Devices – MRI machines, wireless health monitors, and other equipment use high-frequency PCBs to keep medical data accurate and systems working seamlessly.

Defense – communication gear, and electronic warfare systems.

Automotive Systems – advanced driver assistance systems (ADAS) and vehicle radar depend on high-frequency PCBs for real-time data, making roads safer for everyone.

Satellite Communication – RT Duroid 5880 is frequently used in satellite systems where strong signal transmission over long distances is crucial for communication networks.

Common-Used High Frequency PCB Materials in Best Technology

At Best Technology, we use a range of top-quality materials for high-frequency PCBs, depending on the project’s needs. Some of the most popular materials include:

Material	Dielectric Constant (Dk)	Loss Tangent (Df)	Key Features
Rogers RO4003C	3.38	0.0027	Low loss, excellent thermal stability, ideal for RF applications.
Rogers RO4350	3.48	0.0043	Low loss, high thermal conductivity, suitable for microwave applications.
RT/Duroid RO5880	2.94	0.0037	Very low loss, excellent performance at high frequencies, good for multilayer designs.
N4000-13	3.0	0.009	Good thermal stability, low moisture absorption, designed for high-frequency applications.
Taconic RF-60A	6.15	0.0027	High dielectric constant, low loss, suitable for low-loss RF and microwave applications.

Each material brings different strengths for specific applications, giving you the best options for your project.

Discuss Your High Frequency PCB Project with Us Today

If you have a high-frequency PCB project in mind, reach out to us. We’re experienced in creating high-quality PCBs that meet your exact specifications. Whether you need RF, microwave, or other types of high-frequency boards, we’ll make sure your project runs smoothly. Contact us at s ales@www.bestpcbs.com today, and we’ll help you turn your plans into reality.

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4 Layer PCB Layout, Stack-up, Thickness & Design Guidelines

Wednesday, October 16th, 2024

What is a 4 Layer PCB?

A 4 layer PCB is a type of circuit board that consists of four distinct layers of conductive material. Each layer serves a specific function. The layers typically include two signal layers, one ground (GND) layer, and one power (VCC) layer. Generally, through holes, buried holes, and blind holes are used to connect the internal layers. There are more buried and blind holes than 2 layer PCB boards. In addition, try not to run signal track on the two layers of VCC and GND. A 4 layer PCB offers more complex designs, better signal integrity compared to simpler designs.

4 Layer PCB Layout, Stack-up, Thickness & Design Guidelines

4 Layer PCB Stack-up

The typical stack-up configuration is as follows:

Top Layer (Signal Layer): This layer carries signals and connections.

Inner Layer 1 (Ground Plane): This layer serves as a reference for signal return paths, reducing noise and interference.

Inner Layer 2 (Power Plane): This layer distributes power to various components on the PCB.

Bottom Layer (Signal Layer): Like the top layer, it carries additional signals and connections.

4 layer PCB Stack up Options

Generally, there are three main categories for preferred stack-up solutions for 4 layer PCBs:

Solution 1: The standard layer setup for common 4 layer PCBs.

TOP (signal layer)

GND1 (ground layer)

PWR1 (power layer)

BOT (signal layer)

Solution 2: Suitable for situations where key components are laid out on the BOTTOM

layer or key signals are routed on the bottom layer; generally applicable under certain restrictions.

TOP (signal layer)

PWR1 (power layer)

GND1 (ground layer)

BOT (signal layer)

Solution 3: Suitable for PCBs primarily using through-hole components, commonly

used where the power is routed in layer S2, and the BOTTOM layer serves as a ground plane, thereby forming a shielding cavity.

GND1 (ground layer)

S1 (signal layer)

S2 (signal layer)

PWR1 (power layer)

4 Layer PCB Thickness

The thickness of a 4 layer PCB can vary depending on the design requirements. Generally, a standard 4 layer PCB thickness ranges from 0.4mm to 1.6mm. The total thickness is determined by the materials used and the copper weight on each layer. A thicker PCB can offer better thermal management and mechanical stability, making it suitable for high-power applications. Here are the 4 layer PCB thickness with different thickness in Best Technology:

4 Layer PCB Manufacturing Process

Cutting material and grinding → drilling positioning holes → inner layer circuit → inner layer etching → inspection → black oxide → lamination → drilling → electroless copper → outer layer circuit → tin plating, etching tin removal → secondary drilling → inspection →print solder mask→Gold-plated→Hot air leveling→print silkscreen→routing outline→Test→Inspection

Ground Plane Design in 4 Layer PCB

The ground plane in a 4 layer PCB is essential to ensuring good performance and signal integrity. Here’s how to design an effective ground plane:

1. Purpose of the Ground Plane

Reference Point: It provides a stable reference for signals, reducing noise and improving signal integrity.
Return Path: It acts as a low-resistance return path for signals, minimizing electromagnetic interference (EMI).

2. Placement in Stack-up

Typically, the ground plane is placed as one of the inner layers, often Inner Layer 1. This positioning helps shield signals on the top and bottom layers.

3. Continuous Ground Plane

Aim for a solid, uninterrupted ground plane. Breaks or cuts can introduce impedance and increase noise.

4. Vias and Connections

Use vias to connect components to the ground plane. Ensure that vias are placed close to component pads to minimize inductance.
Consider using multiple vias for high-current paths to distribute the current effectively.

5. Thermal and Electrical Considerations

Use thermal vias if heat dissipation is a concern. Place them near high-power components to spread heat away from sensitive areas. Ensure that the ground plane is thick enough to handle the expected current loads without excessive voltage drop.

6. Control EMI

Keep the ground plane as large as possible to effectively shield signals from external interference.
Route high-speed signals away from ground plane edges to minimize crosstalk.

7. Simulation and Testing

Use simulation tools to analyze the ground plane’s performance. Check for potential issues such as ground loops or noise.
After fabrication, test the PCB to ensure that the ground plane functions as intended, with minimal interference.

What is the Advantage of a 4 Layer PCB Over a 2 Layer PCB?

While 2-layer PCB boards have their advantages, multi-layer designs are more beneficial for some applications. Today Best Technology will introduce the difference between 2-layer PCB board and 4 layer PCB.

1. A 4 layer PCB has an inner layer, which is laminated with PP and copper foil on both sides during the lamination process. This is pressed under high temperature and high pressure to form a multilayer board. Some circuits on the PCB 4 layer board are etched through the inner layer and pressed; the 2 layer PCB can be directly cut and drilled after production.

2. The 4 layer PCB is made of four layers of fiberglass, which can reduce the cost of the PCB, but the production efficiency is lower than that of the 2 layer PCB.

3. It is difficult for most people to distinguish a 4 layer PCB by observing the cross-section of the circuit board, but it can be identified by looking at the vias. If the same vias can be found on both sides of the PCB, or if the motherboard or graphics card is facing a light source and the vias do not allow light to pass through, then it is a 4 layer PCB.

4. The PCB 4 layer board has dense routing, with the top layer being the front and the bottom layer being the back.

5. The PCB 4 layer board can distribute wiring among multiple layers, which increases design flexibility and allows better control of differential impedance, single-ended impedance, and improved output for certain signal frequencies.

How to Design a 4 Layer PCB?

When designing a 4 layer PCB, it is important to differentiate between the power layer and the signal layer. The signal layer is a positive output, while the power layer is a negative output. This means that lines drawn on the signal layer will result in actual copper traces, whereas lines drawn on the power layer indicate the removal of copper. Essentially, drawing lines on the power layer corresponds to removing copper, while drawing lines on the signal layer represents creating copper traces. Therefore, when designing the power layer, you can use lines to divide the copper area into separate regions, which is known as “power segmentation.” Here is a simple design step of a 4 layer PCB:

1. Schematic Design and Drawing

2. After completing the schematic drawing, import it into the PCB software, and complete the layout with a simple arrangement.

3. Follow the plan to design the stack-up, paying attention to the following aspects:

You can generate multilayer PCB stack-ups yourself, with the default being two layers.

Choose the unit of measurement.

Pullback: This refers to the inward shrinkage of inner layers. When following the 20H rules during design, the power layer should shrink 40 to 80 mils inward compared to the reference layer. This parameter should be set accordingly.

After adding layers, name them appropriately, such as GND, etc.

4. Complete the routing operation. The negative layer contains a network copper area. Once the settings are complete, click OK.

In conclusion, a 4 layer PCB is a powerful tool in modern electronics, offering enhanced complexity, improved signal integrity, and better thermal management. By understanding its stack-up, thickness, and design guidelines, engineers can create reliable and efficient circuit boards. The advantages of 4 layer PCBs over 2 layer designs make them a preferred choice for many applications.

When you choose a 4 layer PCB, you’re investing in a technology that can support complex designs and improve overall performance. With the right design practices and advanced manufacturing capabilities, the potential for innovation is vast. Whether you’re developing consumer electronics, industrial equipment, or medical devices, a well-designed 4 layer PCB can make all the difference.

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What is Blank PCB?

Monday, October 7th, 2024

What Is a Blank PCB Called?

A blank PCB is commonly referred to as a bare board. This term is used because the board has no components soldered onto it yet. It’s simply the foundation of a printed circuit board (PCB), typically made from a material like fiberglass and copper. The copper traces on the board outline where the electrical connections will eventually be made, but before any components are attached, the board remains “blank.”

A bare board is key point in the manufacturing process of electronic devices. Once components like resistors, capacitors, and integrated circuits are added, the blank PCB transforms into a fully functional circuit board. This is the stage where the blank board evolves, moving from raw material to the heart of a functioning device.

How to Use a Blank PCB Board?

Using a blank PCB starts with designing a circuit schematic. Specialized software is used to create a layout that specifies where each component will be placed and how they’ll be connected through copper traces. Once the design is finalized, the blank board serves as a canvas where components are either soldered by hand or using automated machines in mass production.

If you are working on a DIY project or prototyping, the blank PCB allows for customization and flexibility. You can use a soldering iron to manually attach your components. For large-scale production, automated machines place and solder components onto the blank board with precision. Using blank PCBs for custom designs or modifications is a cost-effective way to experiment with electronics.

Why Is PCB So Cheap?

PCBs are considered affordable due to mass production techniques. Modern manufacturing processes, such as automated assembly lines and the use of standard materials, have significantly reduced costs. The global nature of the electronics industry also plays a role, as many manufacturers source materials and labor from countries with lower production costs.

The materials used, primarily fiberglass and copper, are relatively inexpensive. Furthermore, technological advancements have optimized the process of making PCBs, allowing manufacturers to produce them quickly and in large quantities. The result is that even highly specialized PCBs can be produced at a low cost, making them accessible to hobbyists, startups, and large corporations alike. If you want to know the details about factors affect the price of PCB board, welcome to check our another blog:

How Are Blank PCBs Made?

The process of making blank PCBs is a sophisticated, multi-stage operation that ensures the boards meet high precision standards before any components are added. Here’s a detailed breakdown of the steps involved in manufacturing a blank PCB:

Material Selection and Lamination

Blank PCBs start with a substrate, typically made from fiberglass-reinforced epoxy laminate (FR4), which serves as the board’s structural foundation. This substrate is non-conductive, providing insulation for the circuit. A copper layer is then bonded to one or both sides of the substrate using heat and pressure, forming what is known as a copper-clad laminate. The thickness of this copper layer varies based on the board’s intended application, with typical copper thickness ranging from 1 oz (35 µm) to 2 oz (70 µm) per square foot. Thicker copper layers may be used for boards handling higher currents.

Photoresist Application

After lamination, the copper layer is coated with a light-sensitive material called photoresist. This step prepares the board for the next process, which is exposing the circuit pattern. The photoresist layer can be either liquid or dry film and plays a critical role in protecting certain parts of the copper during etching.

Imaging the Circuit Pattern

The desired circuit pattern, generated from PCB design software, is transferred onto the board. This is done by aligning the photoresist-coated board with a photomask (a stencil-like film) that contains the circuit layout. The board is then exposed to ultraviolet (UV) light. The areas of the photoresist not covered by the photomask are hardened, while the areas shielded by the mask remain soft and will later be removed.

Etching Process

The next step is to remove the unneeded copper from the board, a process called etching. Chemical etchants, like ferric chloride or ammonium persulfate, are used to dissolve the unprotected copper, leaving behind only the circuit traces. The areas of the copper protected by the hardened photoresist remain intact, forming the conductive pathways for the future components.

Drilling Holes for Components

After the etching process, holes need to be drilled into the board. These holes, called vias, allow for the placement of components such as resistors, capacitors, and integrated circuits, and are also used to connect different layers in multi-layer PCBs. Advanced PCB manufacturing often uses computer numerical control (CNC) drilling machines to ensure precision, especially for boards with many layers or small trace designs. Some manufacturers employ laser drilling for microvias.

Plating and Hole Metallization

Once the holes are drilled, they need to be plated to create electrical connections between the different layers of the PCB. This is done through a process called electroless copper plating, which deposits a thin layer of copper inside the drilled holes. The plating process ensures that when components are later inserted, electrical signals can flow between layers through the plated holes.

Solder Mask

After drilling and plating, the board is cleaned and coated with a layer of solder mask. This mask protects the copper traces and prevents solder from accidentally bridging across traces during assembly. The solder mask is typically green, though other colors like blue, red, black, or white can also be used. The solder mask is applied through a screen-printing process or as a dry film, and it is cured using UV light or heat.

Silkscreen Printing

Silkscreen printing is applied to the board to mark component locations, symbols, logos, or other identifiers needed during the assembly process. This layer is typically applied using a silk-screening process, similar to how images are printed onto clothing. White is the most common color used for silkscreen, as it provides high contrast against the green solder mask, but other colors can be used depending on the design.

Surface Finishing

The copper pads, where components will be soldered later, are treated with a surface finish to protect them from oxidation and ensure good solderability. Common finishes include HASL (Hot Air Solder Leveling), where the board is dipped in molten solder and excess solder is blown off with hot air, leaving a smooth surface. Another popular finish is ENIG (Electroless Nickel Immersion Gold), where a thin layer of nickel followed by gold is applied to the copper pads.

Electrical Testing and Quality Control

The final step in producing a blank PCB is electrical testing and quality control. Every trace and connection is tested to ensure there are no shorts or opens, which could render the board useless. Automated Optical Inspection (AOI) systems are used to visually inspect the board for defects, while flying probe tests and bed-of-nails tests check for electrical continuity. Any defects found at this stage are flagged for repair or, in severe cases, the board is scrapped.

What Is the Difference Between Bare PCB and PCB?

The term bare PCB refers to the unpopulated circuit board, which means it lacks any electronic components. In contrast, a PCB refers to a fully assembled board that includes all the necessary components to function.

In the bare stage, the PCB is simply the foundation for the circuit but isn’t functional. Once components are soldered onto the bare PCB, it becomes an operational printed circuit board, ready to be integrated into electronic devices.

How Do You Cut Blank PCB?

Cutting a blank PCB requires precision. Tools such as PCB shears, laser cutters, or CNC machines are commonly used to achieve clean, straight cuts without damaging the copper traces. For smaller DIY projects, a hand saw or scoring tool can be used, but these methods require a steady hand and careful planning to avoid mistakes.

Before cutting, it’s important to mark the board clearly to ensure the cuts are accurate. If the board is part of a larger project, cutting should be done after confirming that all components will fit within the intended space.

Why Are PCBs Green?

The green color on most PCBs comes from the solder mask that coats the board. While green is the most common color, the solder mask can be found in other colors such as red, blue, or black. The preference for green is largely historical, as it provided the best contrast for technicians to inspect the board visually.

Green solder masks also tend to offer better performance under different lighting conditions, which can be helpful during manufacturing and quality control processes.

Do PCBs Use AC or DC?

PCBs can handle both AC (alternating current) and DC (direct current), depending on the design and the type of components used. Some boards are designed specifically for DC circuits, while others are built to handle AC power.

For example, a power supply PCB may convert AC from a wall outlet into DC, which is used by many electronic devices. The flexibility to work with either type of current makes PCBs essential for a wide range of applications.

Blank PCB Board Supplier – Best Technology

With over 18 years as an industry leader, Best Technology is one of the most experienced PCB and PCB assembly manufacturer in Asia. We are highly specialized not only in quick-turn PCB prototype and PCB assembly, but also medium and small volume PCB fabrication. In Best Technology, you can enjoy a full-comprehensive one-stop service from PCB design, layout, PCB fabricate, PCB assembly, function testing and delivery. We always try our best to fabricate your PCB with copper clad laminate with the highest quality to meet your demands.

If you have any questions, please feel free to contact us with sales@bestpcbs.com, we will be happy to help you.

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Can you use AC in PCB?

Monday, October 7th, 2024

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

Can you use AC in PCB?

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

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

Is the circuit board DC or AC?

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

What is the PCB in AC?

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

How to calculate the bandwidth of AC in PCB traces

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

AC in PCB Design Guide

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

AC in PCB wiring

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

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

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

Determination of electrical clearance:

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

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

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

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

Primary side AC to DC part ≥2.0mm

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

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

Secondary side gap ≥0.5mm

Secondary side ground to earth ≥1.0mm

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

Determination of creepage distance:

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

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

(2) Primary side AC to DC part ≥2.0mm

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

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

(5) Secondary side parts ≥0.5mm

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

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

Insulation penetration distance:

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

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

Points to note about wiring process:

Flat components such as capacitors must be flat without glue.

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

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

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

When processing parts, insulation damage should not be caused.

Requirements for flame-proof materials:

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

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

PCB board 94V-1 or above

Regarding insulation level

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

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

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

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

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

The applicable situations of various insulation are as follows:

A. Operational insulation

a. Between parts with different voltages

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

B. Basic insulation

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

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

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

d. As part of double insulation.

C. Supplementary insulation.

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

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

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

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

b. As part of double insulation

D. Double insulation

Double insulation Reinforced insulation

Generally speaking, between the primary circuit and

a. between accessible ungrounded conductive parts, or

b. between floating SELV circuits, or

c. between TNV circuits

Double insulation = basic insulation + supplementary insulation

Note: ELV circuit: extra low voltage circuit

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

SELV circuit: safety extra low voltage circuit.

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

TNV: communication network voltage circuit

Under normal working conditions, the circuit carrying communication signals

Difference between direct current and alternating current

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

‌Direction and polarity:

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

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

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

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

‌Current loss:

DC: Fault losses are relatively small.

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

DC: The voltage cannot be changed using a transformer.

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

‌Application scenarios:

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

FAQ About AC in PCB

FAQ About AC in PCB

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

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

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

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

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

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

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

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

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

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Board electronics with holes

Friday, October 4th, 2024

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

What are the holes in a PCB called?

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

Screw holes: Screw holes are used for fixing.

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

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

What is a through hole

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

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

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

What is a blind via?

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

What are buried vias?

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

What is a microvia?

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

What are Mounting holes？

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

What are Mounting holes？

What are thermal vias?

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

FAQ About board electronics with holes

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

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

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

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

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

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

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

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

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

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

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

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

Choose an appropriate termination method.

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

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

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

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

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

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

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High Frequency PCB Communication Circuits

Friday, October 4th, 2024

Best is mainly engaged in the production of High frequency pcb communication circuits, high-speed, microwave and radio frequency printed circuit boards, mainly in sample making and small and medium batches. The main products are: microwave radio frequency high-frequency boards, Rogers high-frequency boards, Rogers multi-layer high-frequency mixed-pressure boards, Rogers radio frequency boards, Taconic microwave boards, Taconic multi-layer circuit boards, Arlon microstrip antenna boards, ARLON high-frequency boards, F4BM antenna boards, F4BM multi-layer mixed-pressure boards, radio frequency amplifier PCB boards, HDI precision multi-layer boards, serving domestic and foreign high-tech enterprises and scientific research institutions.

‌What is a high frequency pcb communication circuits

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

What is a high frequency pcb communication circuits

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

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

Definition of high frequency pcb communication circuits

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

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

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

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

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

Advantages of high frequency pcb communication circuits

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

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

Classification of high frequency pcb communication circuits

Classification by material:

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

Classification by the hardness of the finished product:

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

Classification by structure:

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

Classification by use:

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

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

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

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

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

Composition and key components of high frequency pcb communication circuits

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

Application of high frequency pcb communication circuits

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

Design Guidelines for High Frequency PCB Communication Circuits

Design Guidelines

High Frequency PCB Communication Circuits

How to avoid high-frequency interference?

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

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

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

How is the differential wiring method implemented?

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

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

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

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

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

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

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

How to deal with some theoretical conflicts in actual wiring?

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

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

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

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

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

About test coupon.

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

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

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

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

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

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

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

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

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

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

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

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Single layer PCB manufacturer | Single sided PCB Design&Prototype

Friday, September 27th, 2024

What is a single-sided PCB circuit board

Single-sided PCB circuit board is a type of printed circuit board. Only one side of the PCB board has circuits (it can have holes or not), and the other side is a substrate or directly covered with insulating ink. There is no circuit and the whole board is transparent under strong light (except for individual boards and special process requirements). The cross section only contains copper foil on the side with circuits.
Single-sided PCB circuit board is obtained by etching copper-clad board. Copper-clad board consists of board base and copper foil. The board base is usually made of insulating materials such as glass fiber, and is covered with a layer of copper foil (usually oxygen-free copper).

Single layer PCB manufacturer

Single layer PCB manufacturer Best Technology has offered high-quality PCBs and the best PCB assembly & box building service all over the world since 2006. We are professional fabricator on PCB prototype, IPC Class III standard are available. You can get high-quality PCB board and PCBA at a very reasonable price.

Single layer PCB design
Best Technology excels in PCB design, perform PI analysis, SI analysis, EMC test and DFM tests to ensure one-time successed PCB design. Over 20 professional engineers, all of them has more than 15+ years experience in PCB, we make sure every design is optimized for performance and manufacturability.

Single layer PCB prototype
As an industry-leading PCB prototype manufacturer, Best Technology offers 24 hours quick turn PCB prototype, PCB assembly and reliable small-batch PCB production. Free technical support and VIP one-to-one service.

Single layer PCB production
With over 18 years PCB manufacture experience, we dedicated to provide highest quality PCB for customers. We offer turnkey service from PCB design, PCB layout, PCB prototype, mass production and PCB assembly. Contact us to get an instant quote.

Single layer PCB assembly
Professional PCB assembly service, includes DFM/DFA checks, function/ICT testing, X-RAY, Online dual AOI, nitrogen reflow oven. 10+ SMT lines, free passive parts and Thorough Inspections! SMT, Thru-hole, BGA, QFN Assembly at Low Prices! No MOQ, complex and difficulty designs welcome!

Single-sided PCB production process

Cutting
Drilling or punching
Screen printing circuit anti-etching pattern or using dry film
Curing inspection and board repair
Screen printing solder mask pattern (commonly used green oil)
Screen printing character mark pattern, UV curing
Preheating, punching and appearance
Electrical open and short circuit test
Pre-coating flux anti-oxidant (drying) or tin spraying hot air leveling
Packaging and delivery

Single-sided PCB production capacity

Item	Content
Material type :	XPC FR-1 FR-4 CEM-1
Surface finish :	ENIG gold, HASL Immersion Tin, Chemical Silver OSP
Layer No :	Single side, Multilayer PCB
Max PCB size:	1500mm*600mm
Min PCB size:	5mm*5mm
Min space/width:	0.1mm
Warp and Twist:	≤0.5%(board thickness：1.6mm，PCB size ： 300mm*300mm)
Board thickness:	0.3-5.0mm
Copper thickness:	35um-240um
Outline Tolerance:	±0.15mm
V-CUT Precision:	±0.1mm
Capacity:	80000㎡/Month
PTH Dia tolerance:	±0.076mm
Outline tolerance:	CNC ：±0.1mm punch：±0.15mm

What are the single-sided PCB materials?

What are the single-sided PCB materials

Phenolic paper substrate
Phenolic paper substrate (commonly known as cardboard, plastic board, V0 board, flame retardant board, red-letter copper clad board, 94V0). The most commonly used product models of phenolic paper-based copper clad boards are FR-1 (flame retardant) and XPC (non-flame retardant). Single-sided copper clad boards can be easily judged from the color of the characters on the back of the board. Generally, red characters are FR-1 (flame retardant) and blue characters are XPC (non-flame retardant). This type of board is the cheapest compared to other types of boards.

Epoxy fiberglass cloth substrate
Epoxy fiberglass cloth substrate (commonly known as: epoxy board, fiberglass board, fiberboard, FR4), epoxy fiberglass cloth substrate is a type of substrate with epoxy resin as adhesive and electronic grade glass fiber cloth as reinforcing material. Its bonding sheet and inner core thin copper clad board are important substrates for making multi-layer printed circuit boards. The working temperature is high and its own performance is less affected by the environment. In terms of processing technology, it has great advantages over other resin fiberglass cloth substrates. This type of product is mainly used for double-sided PCBs. It is also about twice as expensive as phenolic paper substrates, and the commonly used thickness is 1.5MM.

Composite substrates
Composite substrates (commonly known as powder boards, etc., cem-1 boards are also called 22F in some places in China) mainly refer to CEM-1 and CEM-3 composite-based copper-clad boards. Copper-clad boards made of wood pulp fiber paper or cotton pulp fiber paper as core reinforcement materials and glass fiber cloth as surface reinforcement materials, both of which are impregnated with flame-retardant epoxy resin, are called CEM-1. Copper-clad boards made of glass fiber paper as core reinforcement materials and glass fiber cloth as surface reinforcement materials, both of which are impregnated with flame-retardant epoxy resin, are called CEM-3. These two types of copper-clad boards are the most common composite-based copper-clad boards. This type of board is cheaper than FR4 type boards.

Single-sided PCB circuit board price

Since the cost of single-sided PCB circuit boards is affected by many factors, including the cost of raw materials, production cost, production process, special requirements, etc., its exact pricing needs to be negotiated with its single-sided PCB circuit board supplier. The general unit price calculation formula is: (length MM) × (width MM) × 0.01 × unit price (yuan/square meter) ÷ 10000 (rounded to 3 decimal places)
For specific single-sided PCB quotes, please consult bestpcbs．

Single-sided PCB circuit board price

Single-sided PCB applications and features

Single-sided PCBs are increasingly widely used due to their many unique advantages;
High density: For decades, high-density printed boards have developed with the improvement of integrated circuit integration and the advancement of installation technology.
High reliability: Through a series of inspections, tests and aging tests, PCBs can work reliably for a long time (usually 20 years).
Designability: According to the requirements of various performances (electrical, physical, chemical, mechanical, etc.) of single-sided boards, printed boards can be designed in a short time and efficiently through design standardization.
Manufacturability: Through modern production management, standardization, scale (quantification), automation, etc. can be achieved to ensure the consistency of product quality.
Testability: Complete test methods, standards and various test equipment and instruments have been established to detect and evaluate the qualification and service life of a single PCB.
Assembly: Circuit boards facilitate standardized assembly of various components to achieve automated, large-scale mass production. At the same time, circuit boards and various component assemblies can be assembled into larger components and systems, and even complete machines.

Maintainability: Circuit boards and various component parts are manufactured with standardized designs and scales. If a system fails, components can be replaced quickly and conveniently. The system can recover quickly due to this flexibility. More examples include system miniaturization, lightweight, high-speed signal transmission, etc.

FAQ About single sided pcb

FAQ About single sided pcb

Q: When laying out the board, if the lines are dense, there may be more vias, which will of course affect the electrical performance of the board. How can I improve the electrical performance of the board?
A: For low-frequency signals, vias are not a big deal, but for high-frequency signals, try to reduce vias. If there are many lines, you can consider multi-layer boards;

Q: Is it better to add more decoupling capacitors on the board?
A: Decoupling capacitors need to be added with appropriate values at appropriate locations. For example, add them to the power supply port of your analog device, and use different capacitance values to filter out stray signals of different frequencies;

Q: What are the standards for a good board?
A: Reasonable layout, sufficient power redundancy of power lines, high-frequency impedance, and simple low-frequency routing.

Q: How much difference do through holes and blind holes have on signals? What are the application principles?
A: Using blind or buried holes is an effective way to increase the density of multi-layer boards, reduce the number of layers and board size, and greatly reduce the number of plated through holes. But in comparison, through holes are easy to implement in terms of process and have lower costs, so through holes are generally used in designs.

Q: What kind of layout can achieve the best heat dissipation effect?
A: There are three main sources of heat in PCB: (1) heat generated by electronic components; (2) heat generated by the PCB itself; (3) heat transmitted from other parts. Among these three heat sources, the heat generated by components is the largest and is the main heat source, followed by the heat generated by the PCB board. The heat transmitted from the outside depends on the overall thermal design of the system and is not considered for the time being. The purpose of thermal design is to take appropriate measures and methods to reduce the temperature of components and PCB boards so that the system can work normally at a suitable temperature. This is mainly achieved by reducing heat generation and accelerating heat dissipation.

Q: Can you explain the proportional relationship between the line width and the size of the matching via?
A: This is a good question. It is difficult to say that there is a simple proportional relationship because the two simulations are different. One is surface transmission and the other is ring transmission. You can find a via impedance calculation software on the Internet, and then keep the impedance of the via consistent with the impedance of the transmission line.

Q: In an ordinary PCB circuit board with an MCU control, but without high current and high-speed signal requirements, is it better to lay a layer of ground wire around the outermost edge of the PCB to wrap the entire circuit board?
A: Generally speaking, just lay a complete ground.

Q: How to deal with the avoidance of vias during the wiring process of high-speed PCB, what good suggestions are there?
A: For high-speed PCB, it is best to make fewer vias and solve the need to increase vias by adding signal layers.

Q: How to select the thickness of the power trace in PCB board design? Are there any rules?
A: You can refer to: 0.15×line width (mm)=A, and copper thickness also needs to be considered.

Q: When digital circuits and analog circuits are on the same multi-layer board, should analog ground and digital ground be arranged on different layers?
A: This is not necessary, but analog circuits and digital circuits should be placed separately.

Q: How many vias are generally suitable for digital signal transmission? (Signals below 120Mhz)
A: It is best not to exceed two vias.

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