Wide Tuning Range CMOS Colpitts VCO based on Tunable Active Inductor

In this paper, a new differential Colpitts voltage-controlled oscillator (VCO) is presented. The VCO is based on the gm-boosted structure to relax the oscillation start-up current requirement and reduce the DC power consumption in comparison to conventional Colpitts structures. In the proposed VCO, a tunable active inductor is utilized as a part of LC tank instead of passive inductor with constant inductance. The proposed VCO is designed and simulated in ADS in a 0.18?m CMOS process. Simulation results indicate that the proposed VCO has a wide tuning range in comparison to other reported designs while consumes less DC power