Multipin Optimization Method for Placement of Decoupling Capacitors Using a Genetic Algorithm

A genetic algorithm (GA)-based method is proposed for simultaneous optimization of decoupling capacitors assigned to multiple pins of a ball-grid array (BGA) package on a printed circuit hoard. A noise susceptibility parameter is introduced as the basis of a new set of GA fitness functions. Performance of several fitness functions is comparatively tested and discussed in case studies. The accuracy of the developed expressions is tested against full-wave electromagnetic simulation results. The proposed method is particularly useful for predicting the number and placement of decoupling capacitors under the BGA area of integrated circuit devices in early design stages and serves as a complement to rigorous algorithms that are used in the final phase of the design.