A Simulation Study of Colpitts Oscillator Reliability and Variability

Nanoscale CMOS reliability and process variation effect on the LC Colpitts oscillator has been examined. Mixed-mode device and circuit simulation is used to investigate the physical insight of impact ionization to the Colpitts oscillator. An analytical equation of phase noise as a function of offset frequency, transistor parameters, and body bias has been derived. The analytical predictions are in good agreement with ADS simulation results. An adaptive body bias to minimize process variation effect on the Colpitts oscillator has also been proposed. The adaptive body bias technique effectively reduces the hot electron effect and process variability on the Colpitts oscillator performance, as supported by Monte Carlo simulation results.