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) wit h an integrated resonator which satisfies the global system for mobile comm unications (GSM) phase noise requirement at a 3-MHz offset is presented. Th e measured phase noise is -88, -125, and -137 dBc/Hz at 10-kHz, 600-kHz, an d 3-MHz offsets, respectively. The VCO is implemented in a low-cost 0.8-mu m foundry CMOS process exclusively using pMOS transistors which have greate r than one order of magnitude lower 1/f noise than that of nMOS transistors . The tuning range is similar to 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.