A CDMA and AMPS handset power amplifier based on load modulation technique

A new MMlC 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 3ldBc at I8.6dBm and the high power mode exhibits PAE of 37.7% and ACLR of 3ldBc at 28.4dBm. For the AMPS mode operation, the amplifier delivers 2ldBm with PAE of 41.7% and 30.3dBm with 43% in low mode and high mode, respectively.