A Large Tuning-Range LC-VCO Design for Mixer-First Type Receivers

In this paper, a 5 GHz low phase noise CMOS LC voltage-controlled oscillator (VCO) for a mixer-first receiver is presented. By utilizing a five-bit binary-weighted switched capacitor bank, the VCO achieves a tuning range of 50.15% from 3.78 GHz to 6.31 GHz. Designed in TSMC 65 nm CMOS technology, the proposed VCO occupies an area of 725 mu m x 800 mu m. The VCO achieves a phase noise of -121.99 dBc/Hz at 1 MHz offset from the carrier frequency of 6.31 GHz by using a tail inductor in accordance with the 2f(0) filtering topology to improve phase noise. This performance of the VCO has been accomplished by drawing only 10.03 mW of power from the power supply.