Abstract

A new MMIC PA for Cellular & AMPS handsets based on the asymmetric power combining scheme of Doherty amplifier has been developed to boost the efficiency at a low power level. The amplifier has two modes of operation, low and high power modes. At a low power mode, only the main amplifier generates output power and at a high power mode, both the main and auxiliary amplifiers are operational, combining the power efficiently by the load modulation. For the CDMA environment, the amplifier at the low power mode exhibits PAE of 35% and ACLR less than 31dBc at 18.6dBm and the high power mode exhibits PAE of 37.7% and ACLR of 31dBc at 28.4dBm. For the AMPS mode operation, the amplifier delivers 21dBm with PAE of 41.7% and 30.3dBm with 43% in low mode and high mode, respectively.