Differential PLL for Wireless Applications Using Differential CMOS LC-VCO and Differential Charge Pump

A Differentially controlled monolithic LC-VCO along with a differential charge pump are used to implement a differential PLL for substrate noise immunity. The differential VCO control is achieved with minimal increase in the power consumption and without sacrificing the tuning range. In a 0.5 mCMOS technology the measured VCO phase noise is-119dBc @1.0MHz and the tuning range is 26 % of the 1.25GHz center frequency, at a total power consumption of 4.0mA from 3V supply. The common mode rejection of the VCO control lines is more than 2000 at DC. The new differential charge pump architecture provides common mode correction without the need for a clean reference