A highly integrated commercial GaAs transceiver MMIC for 2.45 GHz ISM applications

A highly integrated single chip 3 volt GaAs transceiver MMIC has been developed for wireless local area networks (WLAN). The multi-function chip includes a low noise amplifier (LNA), down mixer, diversity switching, transmit-receive (Tx/Rx) switching and a power amplifier (PA). The chip was fabricated based on a 3 volt GaAs MESFET implant process which was optimized for the multiple sub-circuits. The transceiver MMIC achieved excellent performance over the 2.45 GHz Industrial, Scientific and Medical (ISM) frequency band. This multi-function IC is packaged in a low cost ceramic package to meet cost goals for the commercial market. The fabricated circuits have achieved excellent performance. Typical circuits achieve 19.5 dB small signal conversion gain (antenna to mixer output) and 6 dB noise figure while consuming 12 mA with a 3 volt supply. The mixer and LNA include CMOS compatible enable/disable circuitry to conserve current during standby operation. In the transmit mode, the transceiver MMIC provides an output power of 22 dBm with greater than 50% efficiency. In addition, power control circuitry is included within the power amplifier to provide an adjustable output power and has pulse shaping circuitry to minimize spectral splatter under pulsed bias operation levels.