A 0.6-V, 30-GHz six-phase VCO with superharmonic coupling in 32-nm SOI CMOS technology

This paper presents a six-phase VCO using a superharmonic coupling technique. Three VCOs are coupled by an inductive network in their tail nodes to generate six-phase outputs. This network also serves as a tail noise filter in each VCO. Therefore, the proposed six-phase VCO can achieve better phase noise performance than typical multiphase topologies. The proposed VCO is implemented in 32nm SOI CMOS process with core area of 0.6×0.5mm2. The VCO can be tuned from 29.24 GHz to 31.56 GHz, a frequency tuning range of 7.6% at 0.6V supply. With each VCO consuming 1.52 mW DC power (4.56 mW total), the measured phase noise is -128 dBc/Hz at 10 MHz offset when VCO output frequency is 31.43 GHz, resulting in -191 dBc/Hz of FOM.