A 6 GHz low power differential VCO

This paper presents a new differential CMOS voltage controlled oscillator (VCO). The topology of the proposed differential VCO is a combination of Colpitts CMOS VCO and cross-coupled lateral BJT VCO. A symmetric transformer and differential differentially tuned MOS varactors are used to reduce phase noise. The VCO has been fabricated with the 0.18-μm CMOS process. At the 1.2-V supply voltage, the output frequency of VCO is from 5.99 to 6.43 GHz with 441 MHz tuning range and a phase noise of −118.5 dBc/Hz at the 1 MHz offset from the center frequency of 6.43 GHz. Its core current consumption is 2.8 mA and the core power consumption is 3.36 mW. The total power consumption of this VCO is 9.12 mW. The figure of merit (FOM) of this differential VCO is −189.4 dBc/Hz. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 76–79, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22043