A Low Noise VCO with Common-Tail Inductor in 180nm CMOS Technology

This paper presents a low noise voltage-controlled oscillator (VCO) with common-tail inductor. The “common-mode coupling” topology is adopted to reduce the phase noise and to simplify the coupling network. The proposed common-tail inductor could filter the noise and couple the common-mode voltage from two oscillators. Meanwhile, the common tail inductor structure decreases the number of tail inductor. The proposed VCO is designed and implemented utilizing 180 nm 1P6M CMOS process. The measurement result shows the phase noise is -124 dBc/Hz at 1 MHz offset from 6.24 GHz, and the figure of merit (FOM) is about 187 dBc/Hz while consuming 20 mW with a 1-V supply. The core circuit occupies an area of 1mm×0.8mm.