High efficiency power amplifier module with novel enhancement-mode heterojunction FETs for wide-band CDMA handsets

摘要

A 0.1cc highly efficient power amplifier multi chip module (MCM) employing novel enhancement-mode double-doped AlGaAs/InGaAs/AlGaAs heterojunction FETs (HJFET) has been successfully developed for 1.9GHz wide-band CDMA (W-CD MA) handsets. The HJFET has a 5nm thickness Al{sub}0.5Ga{sub}0.5As barrier layer for improving a gate forward turn-on voltage. It was also optimized with thickness of upper and lower Al{sub}0.2Ga{sub}0.5As electron supply layers to obtain a high maximum drain current. Under single 3.5V operation, the two-stage power amplifier MCM exhibited 26.OdBm output power, a record 47.2 power-added efficiency (PAE) and 22.3dB associated gain at W-CDMA distortion criteria. Even operated at a reduced operation voltage of 2.0V, a high PAE of 46 was achieved. These results indicated the developed MCM is promising for W-CDMA handsets.