A Wideband 9 GHz LC-VCO with Tail Current Source Array in 0.18-μm RF CMOS Process

Abstract

A wideband 9 GHz LC-VCO with tail current source array based on TSMC 0.18-μm RF CMOS process is presented in this paper. After discussing the start-up conditions, the structure of tail current source array is utilized to lower the power consumption in high frequency bands and guarantee start-up at low frequency bands. Furthermore, to extend the frequency range, a 4-bit switched capacitor array is used. Based on our analysis, a NMOS cross-coupled VCO with 4-bit PMOS tail current source array is implemented. Post-simulation results show that the tuning range is from 6.372GHz to 9.154GHz and the phase noise at 1MHz offset is less than-110dBc/Hz in the entire tuning range. The operating current of the VCO core is from 8.24mA to 13.362mA in the entire tuning range under 1.8V supply voltage. And the area of the proposed VCO is 1177.775μm × 577.54μm, with two buffer stages and pads.