A 2.4-to-4 GHz VCO Achieving -137dB c/Hz Phase Noise at 1MHz Offset in 28 nm CMOS

This paper presents a low noise NMOS-only LC-VCO. A tail inductor and a center-tapped spiral inductor are utilized to suppress noise. A wide tuning range is achieved with the help of a switched capacitor bank. Based on the post-layout simulation results, the VCO exhibits a wide turning range from 2.4GHz to 4GHz, and a low phase noise from -132dBc/Hz to -137dBc/Hz at 1MHz frequency offset over the whole operating frequency, which is 10dB better than the conventional VCOs without tail inductor. It consumes minimum 42.8mW and maximum 58.6mW from a 1.8V supply and the VCO core occupies 0.15mm
²
total area in 28nm CMOS process technology.