AN 958: Board Design Guidelines

ID 683073
Date 6/26/2023
Document Table of Contents

1.5.2. Decaps

The on-board discrete decoupling capacitors must provide the required low impedance from a few tens of KHz to about a couple of hundred MHz (maximum) depending upon the capacitor ESR and ESL as well as board mounting and spreading inductance parasitics. Even choosing decoupling capacitors with very low ESR and ESL specifications is not enough as the contribution of the parasitic mounting and spreading inductances can limit the effectiveness of these capacitors. Hence, to design an effective PDS, care must be taken to minimize the various parasitic inductances associated with the design of the board.