Proper Stack-Up in a Multilayer PCB to Reduce Noise Coupling and Improve EMI

摘要

As digital circuits became faster, direct coupling among power planes in multilayer printed circuit boards (PCB) became a major concern for signal integrity/power integrity and electromagnetic interference (EMI). Fast signals produce electromagnetic waves that can propagate by means of the parallel plates in the PCB, induce noise on the signals passing through the power bus (vias) and radiate from the edge of the board. The present study focuses on the analysis of the noise that propagates from a power plane to another power plane due to their proximity. To mitigate this problem, proper design of both power and ground planes in the stack-up is illustrated. A test board is fabricated and measurements are performed in order to validate the numerical electromagnetic model.