A low-noise differential CMOS VCO design in Zero-IF dual-bands 802.11 a/b/g WLAN application

A low noise differential CMOS VCO (voltage control oscillator) design is presented in zero-IF, dual-bands 802.11a/b/g dual-bands WLAN (wireless local area network) application. The VCO is designed to operate at 3.846 GHz as first down-conversion stage local oscillator in dual-bands WLAN receiver, whose noise is dominant to overall system noise performance. Based on noise compressing, filtering technology and low-noise layout deign, the VCO is fabricated in 0.18um RFCMOS 1P6M process and has a measured phase noise of - 116.19dBc/Hz@1MHz, which can well fit the 802.11a/b/g standard requirements. The VCO achieves a tuning range of 590MHz and draws 4mA current from 2.5V power supply. Total die area with guard ring is 600¿m ×700¿m.