A 1.2GHz Frequency Range, 153.4 dBc/Hz FoM, low Phase Noise, Current Starved Multi-Path Ring VCO

This article describes the design of a low power, low phase noise, multi-Path ring VCO (MPRVCO) in 90nm CMOS process. The proposed oscillator achieves a tuning range of 1.2GHz operating at 1.65 GHz center frequency, with reduced phase noise of -87.3dBc/Hz at 1MHz offset. The proposed MPRVCO achieves a FoM of 153.4dBc/Hz, consuming 0.657mW power at 1.65GHz frequency. The proposed VCO utilizes Current starving technique for frequency variation. Sub-threshold transistor is used to obtain monotonic and linear frequency tuning characteristics. The proposed VCO is one of the very few Current Starved ring VCOs capable of producing such low phase noise in 90nm CMOS process while operating in GHz frequency range