A Domain Decomposition Approach for Assessment of Decoupling Capacitors in Practical PDNs

Abstract

A domain decomposition method is proposed to evaluate the effectiveness of decoupling capacitors in practical power delivery networks (PDNs). The proposed method is based on the separation of a PDN into its local and nonlocal domains. The local domain is constituted by circuit components with the highest impact on the impedance of a specified power pin on a planar PDN. The rest of the PDN makes up the nonlocal domain, which could be of any planar shape. The nonlocal domain is characterized as a distributed circuit, preferably using a numerical electromagnetic (EM) simulator. The self-impedance of the pin depends on the placement configuration of capacitors in its surroundings. Using the pin impedance as a figure of merit, the optimal placement configuration is then sought in the local domain. The impact of the stationary domain is included in calculations as an indefinite impedance and the optimal placement configuration of capacitors is computed using an iterative approach. The proposed method avoids the use of a computationally intensive EM simulation at each iteration step, which significantly speeds up the analysis process.