A 2.5 GHz low phase noise LC VCO in 0.35μm SiGe BiCMOS technology

Abstract

A fully integrated low phase noise LC VCO with tail resistor for current control is presented using 0.35 mum SiGe BiCMOS technology. The structure is used to reduce noise of tail current source. The VCO has a tuning range of 480 MHz, from 2.32 GHz to 2.8 GHz and achieves low phase noise of -104.3 dBc/Hz and -124.3 dBc/Hz at 100 kHz and 1 MHz offset frequency from 2.5 GHz carrier. The oscillator draws 5 mA from 5 V supply voltage. The figure-of-merit (FOM) value at 2.5 GHz is around -178 dBc/Hz at the offset frequency of 100 kHz.