Modeling the effectiveness of decoupling capacitors for multilayer PCBs

The ability to rapidly and accurately model the effectiveness of decoupling capacitors on printed circuit boards has been demonstrated. The effectiveness of capacitor placement relative to the true source location is considered, as well as the true impedance of the capacitor across frequency. Since a time domain approach is used, the entire frequency domain response is available via a FFT postprocessing step. This paper describes some preliminary results obtained from Cadence's SpecctraQuest tool along with some measurement validation of the modeling tool.