A low phase noise 2.0 V 900 MHz CMOS voltage controlled ring oscillator

A CMOS voltage controlled ring oscillator with quadrature output is presented. The circuit is designed in a 0.18 /spl mu/m CMOS process and operates on a 2.0 V supply. The VCO has a tuning range of 650 MHz to 1.04 GHz. At 913 MHz the VCO has a phase noise of -116.55 dBc/Hz at a frequency offset of 600 KHz. The average power consumed at 913 MHz is 18.95 mW.