Study of BGA package cap for high-performance computing GPU

GPU for high performance computing shows high current consumption and fast current variation which presents a big design challenge for power delivery. In this paper, power delivery design for a computing GPU is discussed focusing on package capacitors. Current behaviour of a computing application is illustrated first. The related power delivery challenge is presented with simulation and measurement. Next package capacitors are proposed to reduce noise and studied via simulation according to their placement, value, number, and type. Simulation data shows land side cap placed between IO rails and core VDD balls can effectively reduce power delivery noise without compromising BGA density. Measurement data correlates well with simulated power noise. There is about a 55mv noise improvement which yields a gain of 150MHz in GPU operational frequency.