Wide tuning range voltage controlled oscillator (VCO) with minimized phase noise variation in nanoscale CMOS technology

A cross-coupled differential VCO with low phase noise variation is presented. The VCO core adopts a metal-oxide-metal (MOM) digital switching capacitor array (DSCA), which is connected in series and in parallel to the nMOS varactor in order to reduce the KVCO variation. For further gain linearity, wider tuning range and minor phase noise variations, this varactor bank is connected in parallel to three nMOS varactor pairs. Each pair is biased at a different voltage. The proposed VCO has been designed and implemented in UMC 130-nm, 6-metal CMOS technology and operates from 3.45 GHz to 6.23 GHz with 55.6% tuning range, phase noise variations ranging between -134 dBc/Hz and -130.8 dBc/Hz and power consumption below 6 mW at supply voltage of 3.2 V. The simulated phase noise at 1 MHz offset is 132.4 dBc/Hz at 5.0 GHz and a good FOM performance of approximately 204.5 dBc/Hz is achieved.