A 1.1V Low Phase Noise CMOS Quadrature LC VCO with 4-Way Center-tapped Inductor

A 2 GHz series coupled quadrature CMOS LC voltage controlled oscillator (SCQ-VCO) with 4-way center-tapped inductor has been designed in a standard 0.18-mum process. Consuming total 10 mA of current from a 1.1 V power supply, the quadrature VCO achieves a measured single-sideband phase noise of -119 dBc/Hz at 1.0 MHz offset frequency. The VCO achieves -17 dBm of carrier power to a 50-ohm load and tuning range of 200 MHz to meet requirements for the WCDMA standard. Series-coupled technique for achieving quadrature phase lock with low phase error (<0.6deg) and a four-way center-tapped inductor to lower the phase noise is presented.