Power Management Design for PLLs

Phase-locked loops are typically used to provide local oscillators in radio receivers and transmitters, for clock-signal distribution and noise reduction, and as the clock source for high-speed A/D and D/A converters. As PLL noise decreases, the impact of power supply noise increases, and can even limit noise performance in some cases. This article considers basic PLLs and the power-management requirements for each PLL building block.