A 1.8V low-jitter CMOS ring oscillator with supply regulation

This paper presents a low-jitter VCO with on-chip supply regulation. Implemented in a digital 0.18/spl mu/m CMOS process, the design uses only the nominal 1.8V supply. The VCO has a tuning range from 72 MHz to 143 MHz and dissipates 11mW. At 140MHz, the VCO has an measured rms cycle jitter of 7.3ps with no supply noise. The benefits of on-chip regulation are demonstrated by superimposing a 200mVpp, 70MHz sine wave on top of the 1.8V power-supply. Without regulation, the jitter increases to 123 ps; with regulation, however, the measured rms cycle jitter is only 9.4ps.