A 92.6 % tuning range VCO utilizing simultaneously controlling of transformers and MOS varactors in 0.13 µm CMOS technology

A novel resonant circuit consisting of transformer-based variable inductors and MOS varactors is proposed to implement an ultra-wideband voltage-controlled-oscillator (VCO). The VCO is designed and fabricated using 0.13 mum CMOS, and fully evaluated on wafer. The VCO IC exhibits a frequency tuning range as high as 92.6 % spanning from 1.2 GHz to 3.27 GHz. The measured phase noise of -120 dBc/Hz at 1 MHz offset from the 3.1 GHz carrier is obtained.