A low voltage CMOS RF front-end for IEEE 802.11b WLAN transceiver

A low voltage CMOS RF front-end for IEEE 802.11b WLAN transceiver is presented. The problems to implement the low voltage design and the on-chip input/output impedance matching are considered, and some improved circuits are presented to overcome the problems. Especially, a single-end input, differential output double balanced mixer with an on-chip bias loop is analyzed in detail to show its advantages over other mixers. The transceiver RF front-end has been implemented in 0.18 um CMOS process, the measured results show that the Rx front-end achieves 5.23 dB noise figure, 12.7 dB power gain (50 ohm load), −18 dBm input 1 dB compression point (ICP) and −7 dBm IIP3, and the Tx front-end could output +2.1 dBm power into 50 ohm load with 23.8 dB power gain. The transceiver RF front-end draws 13.6 mA current from a supply voltage of 1.8 V in receive mode and 27.6 mA current in transmit mode. The transceiver RF front-end could satisfy the performance requirements of IEEE802.11b WLAN standard. Supported by the National Natural Science Foundation of China, No. 90407006 and No. 60475018.