A broadband highly linear 3.5-6GHz CMOS VCO for multi-standard wireless transceivers

A broadband highly linear Voltage controlled oscillator (VCO) for multi-standard wireless transceivers application is presented in this paper. Highly linear VCO gain (Kvco) is exhibited in the VCO which can realize a linear Kvco, better phase noise performance and more stable oscillation in same time. A 6-bit switched capacitor array is employed to extend the tuning range, and also 6-bit switched current source to guarantee robust start-up condition and maintain the amplitude of different frequency to be approximately the same. Noise filter technology is adopted to further improve the phase noise. The simulated results show the VCO output covers frequency band from 3.5GHz to 6GHz. And the phase noise is -124.6dBc/Hz at 1MHz offset from a 3.5GHz carrier and -116dBc/Hz at 1MHz offset from a 6GHz carrier. The VCO is fabricated in 0.13μm CMOS process while consuming 7.8mA from a 1.2V supply. The total area of layout is 0.75×0.68 mm².