A 6.39GHz–14GHz series resonator mode-switching oscillator with 186–188dB FoM and 197dB FoMA in 65nm CMOS

CMOS LC voltage-controlled oscillators (VCO) with octave frequency tuning-range (FTR) are attractive for wideband radios. An area and power-efficient resonant mode-switching approach is presented that enables wide-FTR oscillators without compromising inductor Q, resulting in low phase noise and high VCO Figure-of-Merit (FoM). The proposed series resonator mode-switching approach results in a 6.4GHz to 14GHz VCO (74.6% FTR) in 65nm CMOS that achieves 186dB–188dB FoM. The scalability of this approach towards achieving even larger FTR is also demonstrated by a triple-mode 2.2GHz to 8.7GHz (119% FTR) VCO.