Controlling simultaneous switching noise with built-in decoupling capacitors

Abstract

This work describes two modeling methodologies to evaluate simultaneous switching noise (SSN) for a four layers printed circuit board (PCB). The first modeling was done using Ansoft Q3D to extract related loop inductances for 16 simultaneous switching outputs (SSO) and estimate the noise voltage. The second modeling was done using Sigrity SPEED2000 to evaluate 128 SSOs and their design practice to keep the noise voltage within 5% of the operational voltage. Simulation results for both tools were also compared and discussed.