Schmitz T., Wong M. AN1325.0 Choosing and Using Bypass Capacitors

Application Note from Intersil Corporation, 2007. — 10 p.This application note aims to bring the design aspect back to this seemingly simple component. After discussing the motivation for using bypass caps, we form a vocabulary around the basics; equivalent circuit, dielectrics and types of available capacitors. The next step is identifying the primary function and
environment of the bypass capacitor. Circuits that exhibit large current spikes have different bypassing needs than ones that solely operate at high frequencies. A few special options are discussed, like scaling multiple bypass capacitors, as well as the importance of board layout. Finally, we present four application examples. These represent circuits with high and low currents as well as those with high and low frequencies.