Fully integrated 10 GHz CMOS VCO

A differential voltage-controlled oscillator has been designed to operate i n the 10GHz band using a 0.25 mum CMOS process and low Q integrated inducto rs. The low gain and low Q problems of the components are overcome by the d eployment of the cascode configuration with negative conductance generation to enhance the loop gain and Q value. PMOS varactors are used for varying the oscillating frequency from 9.7 to 11.4 GHz. The phase noise at 400 kHz offset is from -101 dB/Hz at the low frequency end to -87 dB/Hz at the high frequency end.