GENERAL DESCRIPTION The ML2731 is a power amplifier (PA) bias controller with support circuits for a typical radio transceiver. The IC integrates a PA bias controller, a PA DC switch, a crystal oscillator circuit, a negative voltage generator and two voltage regulators. It can be used with GaAs FETs and silicon bipolar devices. FEATURES ■ Sets PA current and power output using a bias control loop ■ Integrates a PA DC supply switch ■ Prevents PA power-on if negative voltage is not present ■ Integrates all circuits needed for supporting a crystal oscillator with 10MHz to 40MHz frequency range ■ Incorporates a fast starting, high switching frequency, ■egative voltage generator requiring only small ceramic capacitors ■ Contains voltage regulators for an oscillator, a negative voltage generator and a 50mA 3.0V LDO output ■ Requires less than 1mA of current when powered down ■ Supply voltage ranges from 3.3V to 5.5V APPLICATIONS ■ Cellular and Cordless Radios ■ WLAN Radios ■ Radios with GaAs FET Power Amplifiers ■ Fixed and Mobile radio transceivers
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