How to improve EMC in industrial servo multilayer boards?

Using multilayer PCBs is one of the most effective ways to improve the EMC performance of servo systems. Key design considerations for multilayer PCBs from Yinte Electronics: A typical 4-layer PCB stack-up consists of: Top (signal), GND (complete ground plane), PWR (power plane), and Bottom (signal). A complete ground plane provides a return path for high-speed signals and shields against radiation. A 6-layer PCB can add additional ground or signal layers. Key design considerations:

1) Ensure the ground plane is intact and avoid splitting. If splitting is necessary, sensitive signals must not cross the split gap.

2) Place high-frequency, sensitive signals on inner layers adjacent to the ground plane, using microstrip line structures to control impedance.

3) Implement a 20H regular indentation at the power plane edge (H is the interlayer spacing) to reduce edge radiation.

4) Set up an array of grounding vias along the board edge to form "stitching vias" and suppress edge radiation.

Compared to double-sided boards, multilayer PCB design can reduce the overall radiated interference of servo drivers by 10-15dB and significantly improve signal integrity.