30 watt surface-mount power amplifiers for PCS and UMTS applications

Abstract

Small surface-mount power amplifiers have been developed that produce 30 watts of peak power in the PCS and UMTS frequency bands. These two-stage amplifiers exhibit typical gain of 28 dB with good linearity and efficiency under CDMA signal protocols. The designs involve a combination of chip-and-wire plus SMT lumped and distributed matching elements on a thick-film substrate. The thermal design includes two levels of heat spreading through metal base elements before the PCB attachment interface. FET maximum channel temperatures for PCB mounted devices are typically 121 /spl deg/C for 5 W average CDMA output with a +85 /spl deg/C base temperature. The 30 W peak power is believed to be the highest reported for a commercial surface-mount amplifier operating in a microwave band.