A dual-mode zero-IF receiver for dual-band CDMA cellular and GPS

We present a dual-mode receiver for dual-band CDMA 2000 cellular radio, which incorporates an integrated GPS signal path for "E911" emergency call location requirements. The highly integrated zero-IF architecture has separate optimised front-ends, but employs a single shared, reconfigurable baseband path for the two signal bandwidths. The CDMA LO signals are derived from a single external VCO that operates at either twice or 8/9 times the LO frequency at 880 MHz and 1960 MHz respectively, thereby reducing coupling with the transmit path. The circuit is implemented in a 0.25 mum 40 GHz fT BiCMOS process. The chip area is 5 mm²; the CDMA CEL/PCS and GPS receivers consume 108/131 mW and 157 mW respectively, using a 2.7 V supply.