A three-phase PMOS voltage-controlled oscillator using ring and triple-push coupling

ABSTRACT This letter presents a three‐phase VCO consisted of three identical single‐ended Clapp pMOSFET VCOs coupled by a pMOSFET ring and tail inductors. The three‐phase circuit operation is based on the interaction of frequency tripler and divide‐y‐3 injection‐locked frequency divider in addition to the MOSFET‐ring coupling. The fully integrated 8.5 GHz three‐phase VCO was fabricated in 90 nm CMOS process, the frequency tuning range is from 8.08 to 8.94 GHz and the VCO‐core power consumption is 4.04 mW at the supply voltage of 0.88 V. The measured phase noise is −117.18 dBc/Hz at 1 MHz offset frequency from the carrier frequency 8.822 GHz. The VCO occupies a chip area of 0.864 × 0.76 mm2 and provides a figure of merit of −190.1 dBc/Hz. The phase noise is reduced through optimizing capacitor value in the Colpitts negative resistance cell. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2529–2532, 2015