A MONOLITHIC GAAS LINEAR POWER-AMPLIFIER OPERATING WITH A SINGLE LOW 2.7-V SUPPLY FOR 1.9-GHZ DIGITAL MOBILE COMMUNICATION APPLICATIONS

A monolithic linear power amplifier IC operating with a single low 2.7 -V supply has been developed for 1.9-GHz digital mobile communication systems, such as the Japanese personal handy phone system (PHS). Refra ctory WNx/W self-aligned gate GaAs power MESFETs have been successfull y developed for L-band power amplification, and this power amplifier o perates with high efficiency and low distortion at a low voltage of 2. 7 V. without any additional negative voltage supply. by virtue of smal l drain knee voltage, high transconductance and sufficient breakdown v oltage of the power MESFET. An output power of 23.0 dBm and a high pow er-added efficiency of 30.8% were attained for 1.9-GHz pi/4-shifted QP SK (quadrature phase shift keying) modulated input when adjacent chann el leakage power level was less than -60 dBc at 600 kHz apart from 1.9 GHz.