Low standby leakage current power amplifier module made with junction PHEMT technology

A true enhancement-mode junction pseudomorphic HEMT (JPHEMT) with a high threshold voltage (V/sub th/) Of +0.5 V was developed for single-supply power amplifiers. The novel JPHEMT exhibits an extremely low standby leakage current. The leakage current at 25/spl deg/C is 2.2/spl times/10/sup -10/ A/mm and even at 85/spl deg/C is 8.6/spl times/10/sup -9/ A/mm. It is suggested that the leakage current is the lowest among reported enhancement-mode FETs. Moreover, the novel JPHEMT exhibits a high turn-on voltage (V/sub F/) of 1.3 V at 1 mA/mm, which is 100 mV higher than that of a conventional JPHEMT. The PA module performance for 1.95 GHz W-CDMA systems, under conditions of V/sub DS/ of 3.5 V and an adjacent channel leakage power ratio (ACLR) of -37 dBc, demonstrated an output power (P/sub out/) of 26.5 dBm, an associated gain (Gain) of 26 dB and a power added efficiency (PAE) of 47%. The standby leakage current at gate-to-source voltage (V/sub GS/) of 0 V was less than 1 /spl mu/A even at 85/spl deg/C. This high RF-performance, with extremely low leakage current results, indicate that the novel JPHEMT has single-supply amplifier capability.