A Fully-Integrated Direct Conversion Receiver for CDMA and GPS applications

This paper describes a fully integrated zero-IF receiver for cellular CDMA and GPS applications. The single chip zero-IF receiver integrates the entire signal path for CDMA and GPS bands including a low-noise amplifier (LNA), I/Q down-converters, baseband channel selection filters (CSFs), a voltage-controlled oscillator (VCO), and a local oscillator (LO) distribution circuits for each band. The cellular-band LNA achieves noise figure (NF) of 1.2dB, input third-order intercept point (IIP3) of 11dBm, and gain of 15.5dB. Cellular I/Q down-converter and baseband circuitries show 9dB composite NF, 9dBm IIP3, and 60dBm input second-order intercept point (IIP2) without calibration. The measured LO leakage is less than -110dBm at LNA input. The phase noise of cellular VCO is -134dBc/Hz at 900kHz offset with 1.76GHz carrier frequency. Total GPS signal path achieves a NF of 1.7dB, and a gain of 74dB with 42mA current. The receiver is fabricated in a 0.35-mum SiGe BiCMOS process and packaged in a 6mm times 6 mm 40 pin MLF. Handset measurements report that the receiver meets or exceeds all CDMA-2000 requirements