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 /spl mu/m CMOS technology the measured VCO phase noise is -11 dBe @1.0 MHz and the tuning range is 26% of the 1.25 GHz center frequency, at a total power consumption of 4.0 mA from 3 V 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.