Ultra-Wideband CMOS Differential Colpitts VCO with adaptive gm bias for the 60GHz WPAN

A Ultra-Wideband CMOS Differential Colpitts VCO for 60GHz WPAN fabricated with the 90nm TSMC Process is presented. The VCO is composed of a NMOS transistor-pair as a core circuit, 3 bit capacitor array for enhancement of the oscillation bandwidth, and adaptive gm bias for desensitizing process variations. The proposed architecture can operate at 28~34GHz and the phase noise at 1MHz offset is -112dBc/Hz. The power consumption of the VCO including inherent buffer is 21.6mW. Compared with previous studied works, the proposed VCO has the widest bandwidth at mm-Wave frequency.