A Low hase Noise Quadrature LC-VCO in 0.18-μm CMOS Technology

A 5.2-GHz quadrature LC voltage controlled oscillator (VCO) has been designed in a standard 0.18-μm CMOS process. Digitally controlled switch array is used in this design to achieve sufficient frequency tuning range and low phase noise. The oscillation frequency can be tuned from 5.03 GHz to 5.32 GHz through the 2-bit switch array. With the selection of an optimal on-chip inductor, the quadrature VCO achieves a single-sideband phase noise of -116dBc/Hz at 1.0 MHz offset frequency consuming total 9.8mA of current from a 1.5 V power supply.