Optimization and modeling of resonant clocking inductors for the POWER8TM microprocessor

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 POWER8^TM 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.