Design of power-efficient CMOS based oscillator circuit with varactor tuning control

This paper presents a low-power, wide tuning range CMOS voltage-controlled oscillator with MCML (MOS current mode logic) differential delay cell. Voltage controlled oscillator (VCO) circuit is designed in TSMC 0.25 mu m CMOS process. To achieve the broad frequency range concept of variable capacitance is employed in the proposed VCO circuit. Source/drain tuning voltage (V-tune) and body bias voltage (V-b) of I-MOS varactor are used to achieve variable capacitance at different I-MOS varactor widths (W). The dual control voltage of I-MOS varactor results in a tuning range from 0.528 GHz to 2.014 GHz. VCO's figure of merit (FoM) is 152.13 dBc/Hz with phase noise of -93.77 dBc/Hz at 1 MHz offset from the oscillation frequency. The proposed VCO dissipates maximum power of 3.127 mW.