Analysis of Switching Noise on Power Planes

Abstract

Power delivery networks (PDNs) in modern printed circuit boards (PCBs) are usually realized using power planes. Since the planes have very low inductance, it is usually believed that such PDNs have the smallest amount of switching noise. However, in reality, the power planes can resonate. The noise at resonant frequencies can be significant and it deteriorates the PDN performance. One of the classical methods for decreasing the noise is bypassing. This paper investigates the behavior of a typical PDN and the effect that real SMD bypass capacitors produce when attached to it.

Keywords

• Power-delivery networks
• switching noise