The clock distribution of the Power4 microprocessor

Abstract

The clock distribution on the Power4 dual-processor chip supplies a single critical 1.5 GHz clock from one SOI-optimized PLL to 15,200 pins on a large chip with 20 ps skew and 35 ps jitter. The network contains 64 tuned trees driving a single grid, and specialized tools to achieve targets on schedule with no adjustment circuitry.