A multistandard Σ-Δ fractional-N frequency synthesizer for 802.11a/b/g WLAN

Abstract

A multistandard WLAN fractional-N frequency synthesizer is implemented in 0.13-mum CMOS. The PLL is able to generate carrier frequency for 802.11a/b/g and Hiper- LAN2 standards. Given the wide tuning range required, the VCO adopts a switched tuning LC tank together with an Adaptive Frequency Calibration (AFC) technique. Measured integral phase noise is less than 3deg rms and the 40-MHz reference spurs are below -40 dBc. Lock time is less than 200 musec. The power consumption is about 50 mW from a 1.2- V supply.