A Wide-band Low Noise Quadrature CMOS VCO

A wide tuning range and low noise CMOS quadrature voltage-controlled oscillator (QVCO) using 0.18-mum 1P6M standard CMOS process is proposed in this paper. The VCO is realized employing switchable capacitors, so as to work in dual band and increase operation frequency. Moreover, the dual band operation could decrease the tuning sensitivity in each band and hence lower the phase noise. The VCO operates from 5.14 to 6.3 GHz with more than 20% tuning range. The measured phase noise at 1-MHz offset is -120.2 dBc/Hz at 5.5 GHz with VCO cores drawing total current of 8 mA at 1.8 V supply and the output power is about 1.5 dBm