A Low Phase Noise Quad-Band CMOS VCO with Minimized Gain Variation for GSM/GPRS/EDGE

A differential LC VCO is presented for commercial quad-band GSM/GPRS/EDGE applications. The VCO is designed in 0.13
μ
m CMOS process and meets stringent phase noise specifications. A technique to minimize the VCO gain variation is presented which reduces the
K_vco
variation to
±14%
; more than three times smaller than the previous solutions. This technique results in reduction of the delay mismatch between the amplitude and phase paths in a polar loop transmitter.