Design and realization of a process and temperature compensated CMOS ring oscillator

Abstract

This paper describes the design and realization of a process and temperature compensated CMOS ring oscillator. The proposed circuit employs a current-starved ring oscillator with a compensated bias circuit, which generates an adaptive control voltage to maintain a fixed oscillation frequency against temperature and process variations. Simulation results using process parameters from a 0.18-μm CMOS technology and 1.8-V power supply voltage showed that the worst-case frequency variation of 4.49% and 2.29% could be obtained at the oscillation frequencies of 100 MHz and 150 MHz, respectively, over the temperature range of - 40°C to 125°C. The overall circuit consumes 437μW at 100MHz and 537μW at 150MHz.