5-GHz gm-boosted transformer cross-coupled current-reused colpitts VCO

This paper presents the design of a 5 GHz g m -boosted transformer cross-coupled current-reused Colpitts voltage-controlled oscillator (VCO). The gm-boosting techniques of transformer cross-coupling is adopted to make the oscillation startup condition much easier with a lower current consumption. This Colpitts VCO is implemented in TSMC 0.18μm 1P6M CMOS process with a chip area of 0.655 mm2. The measured frequency tuning range is from 4.63 to 5.04 GHz, and the phase noise is −116.79 dBc/Hz at 1 MHz offset. The VCO core dissipates 3.74 mW from a 1.8 V supply.