A 1.24-GHz monolithic CMOS VCO with phase noise of -137 dBc/Hz at a 3-MHz offset

For the first time, a 1.24-GHz CMOS voltage-controlled oscillator (VCO) with an integrated resonator which satisfies the Global System for Mobile communications (GSM) phase noise requirement at a 3-MHz offset is presented. The measured phase noise is -88, -125, and -137 dBc/Hz at 10-kHz, 600-kHz, and 3-MHz offsets, respectively. The VCO is implemented in a low-cost 0.8-μm foundry CMOS process exclusively using pMOS transistors which have greater than one order of magnitude lower 1/f noise than that of nMOS transistors. The tuning range is /spl sim/130 MHz for the control voltages between 0.5 and 3.0 V. The VCO core runs on 22 mA from a 3-V power supply.