Le Leivre.com

Capacitor Self Resonance

This note shows how chip a capacitor's self resonant frequency varies with its value. It is often required to AC couple RF circuits or to decouple supply rails and this can be done most effectively by targeting the specific frequencies known to be present.



The figure above plots the Self Resonant Frequency for a range of values of 0402 & 0603 capacitors made from both COG and X7R dielectric materials. Click the picture for a larger view
Package inductance series resonating with the part capacitance is the main contributor of the SRF and typically this is very similar for most vendors of these small SMD capacitors. Differences do appear however for specialist highQ and high voltage parts.

Note* Measurements from Murata GRM15 GRM18 ranges of general purpose capacitors.