A 1.4mW 4.90-to-5.65GHz Class C CMOS VCO with an Average FoM of 194.5dBc/Hz

A class-C CMOS harmonic VCO is presented. The oscillation amplitude is maximized by the active devices operating in class-C, while the bias current noise is naturally rejected by the topology. Drawing 1.4mA from a 1V power supply, the 0.13um CMOS prototype displays an average phase noise of -130dBc/Hz @ 3MHz over the 4.90-5.65GHz tuning range, for a figure-of-merit of 194.5dBc/Hz