A MATLAB tool to optimize the selection of the decoupling capacitors in a PDN

Abstract

For a good reliability, the Power Distribution Network (PDN) should meet target impedance across the frequency range of direct current, up to the highest frequency of interest. Using decoupling capacitors is a good mean to maintain the impedance of a PDN below a specified level, [3][4][5]. Decoupling capacitors are used to obtain low power supply impedance in the MHz range. Decoupling capacitors have traditionally been modeled as a series RLC network. Capacitors vendors describe the specifications in terms of its capacitance, equivalent series inductance and equivalent series resistance. The RLC components are constant with frequency and are easily identified in the Bode plot. There are several commercial tools available to help in selecting the decoupling capacitors, but the goal of this paper is to present a MATLAB tool that helps us reduce the time of simulations and optimize the process of selecting the decoupling capacitors.