A 1.3 GHz low-phase noise fully tunable CMOS LC VCO

This paper presents a low-phase noise CMOS LC-VCO, in which a complete compensation of the component spread, due to process variations, can be done. The LC tank is made of a metal-oxide-silicon varactor and a bondwire and a spiral inductor in series. The trade-off between VCO gain variations and phase noise is introduced. The measurements performed on a prototype, powered by a 2-V supply, realized in a digital CMOS process, are presented. The oscillation frequency can be varied in the range 1.1-1.45 G-Hz. The measured phase noise at an offset of 600 kHz from a 1.3-GHz carrier is -119 dBc/Hz, with 6-mA current consumption.