2013 Volume 10 Issue 13 Pages 20130323
An LC-tuned sinusoidal voltage-controlled oscillator (VCO) using temperature-stable linear operational transconductance amplifiers (OTAs) is presented. Its architecture is based on Colpitts oscillator configuration, where the inductor is simulated one realized with four OTAs and a grounded capacitor. A prototype VCO built with discrete components exhibits less than 3% nonlinearity in its current-to-frequency transfer characteristic from 0.7-40MHz and 95ppm/°C temperature drift of oscillation frequency over 0 to 75°C. The total harmonic distortion (THD) is as low as 2.9% with a peak-to-peak amplitude of 0.7V for a specified frequency-tuning range. The phase noise of the VCO is about -105.2dBc/Hz at 1MHz offset frequency.