-Boosted Complementary Current-Reuse Colpitts VCO With Low Power and Low Phase Noise

In this letter, a transformer-based current-reuse Colpitts voltage controlled oscillator (VCO) is proposed, which combines a N-type and P-type Colpitts oscillators using a 5-port transformer in a complementary form to provide the differential outputs. The proposed VCO has low phase noise due to the low noise Colpitts oscillator topology and the negative-Gm boosting technique with half of the DC-current consumption using the current-reusing method. The proposed VCO has the frequency tuning range from 8.57 to 10.21 GHz, and shows low phase noise of -110.6 dBc/Hz at 1 MHz offset frequency at 9.41 GHz and high figure of merit with tuning range (FoMT) of -191.8 dBc/Hz. The power consumption is 2.1 mW from 1.2 V supply voltage. The VCO is implemented using 0.13 μm CMOS process with chip area of 0.45 mm2.