A new design of low power varactor based voltage controlled oscillator

Abstract

This paper reports a new design of voltage controlled oscillator (VCO) using three transistors NOR-gate with metal oxide semiconductor (MOS) varactor tuning concept. The proposed VCO has been designed in 0.18 μm TSMC CMOS technology. Control voltage (VCT) across the MOS varactor has been varied to achieve the tuning in proposed VCO circuit. Reported VCO topology exhibits a wide tuning range from 2.781 to 4.062 GHz with the variation in control voltage (VCT) from 0 to 0.8 V with different value of supply voltage (VDD). Further, a tuning range has been observed from 1.019 to 3.777 GHz with variation in supply voltage (VDD) from 1 to 3 V. VCO shows power consumption from 0.130 to 5.685 mW with varied power supply voltage from 1 to 3 V. The proposed VCO shows phase noise of − 87.6 dBc/Hz at 1 MHz offset from the center frequency with power consumption of 1.270 mW. The figure of merit of the proposed VCO is 155.4 dBc/Hz. Proposed ring VCO shows low power consumption, wide tuning range and superior phase noise performance in comparison to the previously reported circuits.