Silicon bipolar linear power amplifier for WCDMA mobile applications

A monolithic 1.9-GHz linear power amplifier for wideband code-division multiple access wireless transmitters was integrated using a low-cost pure-silicon bipolar process. At a 3.3-V supply voltage, the circuit exhibits a 31-dBm saturated output power, 57% maximum power-added efficiency, and 29-dBm output 1-dB compression point, while using a low quiescent current of 80 mA. Thanks to a linearizing bias network, the power amplifier is able to comply with the standard -33-dBc adjacent-channel leakage power ratio specification up to a 28.3-dBm output power level. The circuit also features temperature-stable RF gain as well as quiescent current control and shut-down functionalities.