Low power consumption, low phase noise ring oscillator in 0.18 μm CMOS process

In this work, a new ring voltage controlled oscillator with a two cross coupled load PMOS transistors is proposed. The proposed method preserves the maximum frequency of the VCO unaffected which leads to improvement in phase noise and the power consumption of VCO oscillators. The proposed ring oscillator implemented in 0.18μm CMOS shows the worse phase noise of -108 dBc/Hz at 10MHz offset, tuning range of 140.7%, while dissipating a maximum power consumption of 9 mW from 1.8 V supply. Keywords— Ring oscillators, VCO, tuning range, phase noise, cross coupled PMOS transistors.