Electromagnetic compatibility in high-speed signal PCB design issues
o-lead
o-leading.com
2018-06-01 15:21:06
1,3W and 20H rules
3w is the wiring spacing between the signal lines is twice the line width, the center distance is 3 times, as shown in Figure 1
Electromagnetic compatibility issues that PCB（High quality pcb manufacturer） design should pay attention to
The 3W line spacing can ensure that the electric field is no more than 70% from other interference signals. If the 98% electric field does not interfere with each other, a 10W spacing is used.
20H means that the power plane of the multilayer board is more than 20 times larger than the distance between the two planes. In this way, the power source is surrounded by the ground plane, greatly reducing the probability of outward radiation. As shown below
Electromagnetic compatibility issues that PCB design should pay attention to
2, high-speed signal routing level selection
The high-speed signal line is best to walk in the inner layer, so that the dielectric layer plays a shielding role and can effectively suppress the outward emission of the EMI signal.
For high-speed signal lines, such as clock money, it is best to use packet processing, and the package is connected to the ground every 3000mil. The 3W rule should be satisfied between the key signal and other lines. As shown below
Electromagnetic compatibility issues that PCB design should pay attention to
4, metal shell to ground.