A low phase noise wide tuning range CMOS quadrature VCO using cascade topology

A new fully integrated 2.4GHz CMOS quadrature voltage control oscillator (VCO) is presented. It achieves low phase noise at quadrature outputs using the proposed cascade coupling topology. Digitally-controlled capacitor bank is designed for wide tuning range from 2.4 to 2.9GHz. By a standard 0.25 /spl mu/m single-poly CMOS process with thick top metal, total power consumption of two VCO cores and buffers for generating quadrature signal are 6mA and 12mA respectively. Measured phase noise at 1MHz offset from the center frequency is -114dbc/Hz.