A 1.9-GHz cmos power amplifier using an interdigitated transmission line transformer

Abstract

A 1.9-GHz CMOS differential power amplifier for polar transmitter applications is designed using a 0.25-mu m RF CMOS process. The input transformer and output transformer are fully integrated on the chip. The transmission line transformer is used as an output power combiner and an output matching component. To increase the coupling factor of the transformer, an interdigitated transmission line transfomer is used and it achieves a drain efficiency of 28% at the maximum output power. The maximum output power is 28.2 dBm with a 1.8-V supply voltage. (c) 2007 Wiley Periodicals, Inc.