Optimization and modeling of resonant clocking inductors for the POWER8^TM microprocessor

Abstract

A parameterized model for resonant clocking inductors embedded in a dense power grid was developed using extensive electromagnetic simulations. The resulting model was used to support resonant clock designs for the POWER8TM microprocessor. The model enabled tuning of the inductance attached to each clock sector to optimize its resonant behavior, resulting in a 33% reduction in clock power. Simulations using the model showed excellent agreement with measurement for inductance, Q and global clock power. Inductor to inductor and inductor to flip-chip solder ball interaction was minimized by shielding provided by the dense power grid.