A 350mV Complementary 4-5 GHz VCO based on a 4-Port Transformer Resonator with 195.8dBc/Hz Peak FOM in 22nm FDSOI

Abstract

This paper presents an ultra-low voltage and power complementary VCO topology based on a 4-port transformer resonator. The design benefits from the high current efficiency of a CMOS topology and the low phase noise and supply voltage of the NMOS/PMOS-only structure without sacrificing reliability. A 4-port transformer resonator is used to provide two differential-mode (DM) and two common-mode (CM) harmonic impedances for lower phase noise, voltage supply, and sensitivity to CM tuning. The CMOS VCO is implemented in 22nm FDSOI with a core area of 0.19 mm2. The VCO dissipates < 0.45mW from 350mV supply while achieving a peak figure-of-merit (FOM) of 192-195.8 dBc/Hz across the 20% continuous tuning range of 4.06-to-4.96 GHz. To the authors knowledge, the 4-port resonator-based CMOS VCO has the highest reported FOM for oscillators with sub-0.5mW power consumption and the lowest supply voltage (350mV) for complementary designs.