Power level-dependent dual-operating mode LDMOS power amplifier for CDMA wireless base-station applications

The design and analysis of a dual-operating mode laterally diffused metal-oxide semiconductor (LDMOS) power amplifier for code-division multiple-access wireless communication base-station applications is presented in this paper. The amplifier structure consists of four parallelly located single-stage LDMOS amplifier array, the dual-mode input power divider, and output power combiner. In this dual-mode operation, the number of operating power amplifier (either one or four amplifiers) is controlled depending on the required power level. This results in significant improvement in efficiency performance of the amplifier by minimizing unnecessary dc power consumption. In addition to the enhancement of efficiency, the amplifier design approach also provides better overall linearity performance. The proposed dual-operating mode design technique was successfully demonstrated by designing, implementing, and testing an LDMOS power amplifier with Motorola MRF 21030 in this study.