A K-band CMOS low power modified colpitts VCO using transformer feedback

Abstract

A K-band low-power, low phase noise modified Colpitts VCO was implemented in 0.13 mum CMOS process. The timed current switches of the conventional Colpitts VCO are replaced by a differential transformer, and thus the supply voltage of the proposed VCO can be reduced. The VCO has -100 and -109.5 dBc/Hz phase noises at 1 MHz offset under 4 and 10 mW dc power consumptions, respectively. The chip size is 570 times 570 mum <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> .