Low-power high-tuning range CMOS ring oscillator VCOs

This paper presents the design of two new ring oscillators based on differential and single-ended topologies using a 0.13 mum 1P8M CMOS technology. The differential oscillator utilizes feed-forward technique and a new composite load with inductive impedance, reducing the delay per stage and widening the tuning range. The output frequency ranges from 0.5 to 9.5 GHz and the circuit consumes only 9 mW. The simulation result of phase noise is -85.3 dBc/Hz @ 1 MHz offset from centre frequency. The single-ended ring oscillator with inductive composite load oscillates from 6.3 to 13.9 GHz and consumes only 5.1 mW with phase noise of -81.5 dBc/Hz @ 1 MHz offset from centre frequency.