A high-swing complementary class-C VCO

Abstract

This paper presents a high-swing VCO combining the efficiency of the class-C oscillator with that of the complementary PMOS-NMOS topology. Moreover, removing the traditional tail current source, the VCO exhibits an even larger swing, maximizing the phase noise performance. Designed in a 90nm CMOS process, the VCO operates between 3.3GHz and 4.4 GHz, for a 28% tuning range. Drawing 1.8mA from 1.2V, the phase noise is -142 dBc/Hz at a 10MHz offset from a 4.4GHz carrier. The resulting phase-noise FoM is 191.5 dBc/Hz and varies 1.5 dB across the tuning range.