A temperature-compensated high-frequency CMOS integrated relaxation oscillator with low frequency variations is presented. A current-controlled oscillator topology is employed with a resistive source-degenerated transconductor and a current comparator to achieve high oscillation frequency and low power dissipation. The proposed oscillator was designed with process parameters from a standard 0.35-μm CMOS technology and a 2.5-V single power supply voltage. At a nominal oscillation frequency of 21 MHz, the total power dissipation of the circuit was 201 μW. Post-layout simulation results showed that the frequency variations were less than 34.16ppm/∘C over a temperature range of -40 to +120∘C.
