Colpitts VCO using temperature-stable linear OTAs

Abstract

Abstract: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 currentto-frequency transfer characteristic from 0.7-40 MHz and 95 ppm/ • 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 0.7 V for a specified frequency-tuning range. The phase noise of the VCO is about −105.2 dBc/Hz at 1 MHz offset frequency.

Hartley-VCO Using Linear OTA-based Active Inductor

“…3 (b) with the broken line, indicating that the temperature drift is less than 220 ppm/℃ over the frequency range of 0.96 to 42.62 MHz. This drift is about 4.5 times lower than that of the previous work described in [9] and about two times higher than that of the Colpitts VCO in [1].…”