The clock distribution of the Power4 microprocessor

The clock distribution of the Power4 microprocessor was studied. This distribution on the Power4 supplies a single critical 1.5 GHz clock from one SOI-optimized phase locked loop (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.