An ultra low voltage, low power, fully integrated VCO for GPS in 90 nm RF-CMOS

A fully integrated 0.6 V VCO for the GPS L1 band is realized in a 90 nm RF-CMOS process. The purpose of the design is to demonstrate how suitable deep submicron CMOS transistors are for ultra low voltage, low power oscillator design. The VCO operates at 6.3 GHz and a divide-by-four circuit buffer provide the wanted 1575.42 MHz signal. Measured phase noise is for a 0.6 V supply voltage and bias current of 2.6 mA - 122 dBc/Hz at 1 MHz offset, measured for a 1.58 GHz carrier. The phase noise of the VCO has been measured for different bias point showing good agreement between measured results and theory.