Design And Analysis Of Low Power Low Phase Noise VCO

Abstract

In this paper, a novel methodology to implement a LC tank voltage controlled oscillator (VCO) with lower phase noise is proposed and verified. A relationship between the phase noise, power consumption and the bias current is fully analysed to improve the performance of the VCO. The architecture of the VCO employs two current mirrors one at the top of the cross-coupled complementary VCO and the other at the tail end to balance the impedance and give the exact replica of the current in both the arms of current mirror circuit. The phase noise measured is -110.9 dBc/Hz at the offset frequency of 100KHz, -126.4 dBc/Hz at 600kHz and -140.5 dBc/Hz at 3MHz from the carrier frequency. The VCO consumes only 1.72mW of power at 2V supply. Results show that a 33% reduction in power consumption is achieved as compared to the VCO using a tail current mirror and 46.75% to the VCO without current mirrors