DOUBLE-DOPED POWER HETEROJUNCTION FET FOR 1.5 V DIGITAL CELLULAR APPLICATIONS

This article describes 1.5 V operation power performance of a double-d oped AlGaAs/ InGaAs/AlGaAs heterojunction FET (HJFET) for personal dig ital cellular phones. A 1.0 mu m gate length HJFET exhibited 600 mA mm (-1) maximum drain current, 260 mS mm(-1) transconductance (g(m)) and 9.4 V gate-to-drain breakdown voltage. Operated with a drain bias of 1 .5 V, a 28 mm gate width HJFET demonstrated 1.02 W (30.1 dBm) output p ower and 45.2% power-added efficiency with -50.3 dBc adjacent channel leakage power at 50 kHz off-center frequency. This excellent power per formance under 1.5 V operation was discussed with a low on-resistance of 2.5 ohm mm as well as with linear g(m) characteristics around an op erating bias point. (C) 1997 Elsevier Science Ltd.