A low power wide tuning range two stage ring VCO with frequency enhancing

Abstract

A wide tuning range frequency enhanced two stage ring voltage controlled oscillator (VCO) is proposed in this letter. The proposed delay cell increases the transmission gain by inserting a resistor between input and output, which consumes lower power to generate same oscillating frequency. A rail-to-rail effective voltage tuning range is obtained by both tuning of tail current and the strength of cross coupled latch. It is important for advanced process, which has low standard supply voltage and high threshold voltage. The proposed VCO is fabricated in TSMC 40 nm CMOS technology. The measured phase noise of proposed VCO is −98.05 dBc/Hz at 1 MHz offset with 1.38 GHz carrier frequency while consuming 1.1 mW from a 1.1 V standard supply. The figure of merit (FoM) is 160.4 dBc/Hz.