A wideband CMOS voltage-controlled oscillator with switched-capacitor array

In this paper, a wideband CMOS LC VCO operating from 1.8 GHz to 3.0 GHz has been presented. The VCO is realized utilizing a standard 0.18 µm CMOS technology. The design utilizes 6-bit binary switched-capacitor array to realize 55 % tuning range. An automatic frequency calibration (AFC) circuit that could generate the control-code to select the optimum frequency sub-band is also designed. The measurement results showed that the realized VCO exhibits a wide tuning range from 1.75 GHz∼3.04 GHz. At the center frequency of 2.4 GHz, a phase noise performance of −101 dBc/Hz at 100 KHz offset and −122 dBc/Hz at 1 MHz offset has been achieved.