At present, high-speed PCB design is widely used in the fields of communication, electronics, computers, graphics and image processing, etc. All high-tech value-added electronic product designs are pursuing miniaturization, lightweight, low power consumption, low electromagnetic radiation, high reliability and other characteristics. In order to achieve the above goals, engineers need to master the key points in high-speed PCB design.
The key points of high-speed PCB design (general)
1. Design of power supply circuit
The power supply is the basis for the stable operation of an electronic product. Although the technical challenge of power supply design is not the greatest most of the time, once there is a problem of operational stability, it is often related to the power supply.
The focus of power supply design is mainly on the functional design optimization of the power module, the improvement of conversion efficiency, and the design of power supply channels, which must follow the corresponding technical indicators and rules. For sensitive power supplies or power supplies with large currents, PI simulation is also needed to improve the performance of DC voltage drop, dynamic impedance and noise.
2. Design of high-speed parallel signals
The most common are ddr3, ddr4 and other circuits. Especially for Memory Down design, special attention should be paid. While strictly implementing the original Layout Guide, it is best to use simulation analysis to assist in optimizing the layout and wiring design to ensure the design quality of high-speed signals.
There are many other types of parallel signal designs. Generally, according to the corresponding chip design rules, the absolute length and relative length are controlled. At the same time, the number of vias, signal cross-division, and crosstalk rules are well controlled to meet most design requirements.
3. High-speed serial signal design
In recent years, high-speed serial signals have developed very rapidly. Many traditional parallel bus interfaces are gradually being replaced by serial buses. For example, the most typical IDE parallel hard disk data interface has been replaced by the SATA serial data interface. I believe that the application of high-speed serial signals will become more and more extensive in the future.
At present, the most common PCIE high-speed channels, as well as SATA, SAS, LVDS, USB3.0 high-speed channels, and high-speed optical network channels, have generally increased their signal speeds to 5G, 8G, 10G, 28G, and even 56Gbps. Therefore, the design must be carried out in strict accordance with the corresponding high-speed design rules, and the signal integrity analysis and optimization must be done well, otherwise it will be easy to have problems with signal quality.
4. Others
In addition, there are many key technical points that need to be paid attention to, such as analog signal design, RF signal, digital-analog mixing, and DFM, DFA, EMC design points, etc. Each direction has a series of rules and requirements.
Reminder: High-speed PCB design needs to face many different product directions. Although some basic technologies are universal, many industries also have their own technical differences, because the core design requirements of a field are different. For example: consumer products highlight the performance-price ratio; on the contrary, the military and industrial fields require absolute reliability; and the data and communication fields require extreme product performance. Therefore, while mastering the relatively common core key points of high-speed PCB design mentioned above, we must also respond flexibly to products in different fields.