Method for effective placement of on-chip decoupling capacitors determined by maximum effective radii

Abstract

The maximum effective radii of an on-chip decoupling capacitor based on a target impedance (discharge) and charge time are determined. To be effective, an on-chip decoupling capacitor should be placed such that both the power supply and the current load are located inside the appropriate effective radius. If this allocation is not feasible, the current load is partitioned into several circuit blocks, reducing and distributing the localized current demands. The on-chip decoupling capacitors are allocated to each block while satisfying both effective radii criteria.