A wide-bandwidth low-voltage PLL for PowerPC microprocessors

Abstract

A 3.3 V Phase-Locked-Loop (PLL) clock synthesizer implemented in 0.5 /spl mu/m CMOS technology is described. The PLL supports internal to external clock frequency ratios of 1, 1.5, 2, 3, and 4 as well as numerous static power down modes for PowerPC microprocessors. The CPU clock lock range spans from 6 to 175 MHz. Lock times below 15 /spl mu/s, PLL power dissipation below 10 mW as well as phase error and jitter below /spl plusmn/100 ps have been measured. The total area of the PLL is 0.52 mm/sup 2/.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>