Although class-A power amplifiers (PA) are best in terms of linearity, their efficiency is rather poor as compared with other amplification classes such as “AB”, “C” and Doherty amplifiers. However, higher efficiency leads to higher nonlinearity and PA output will be distorted, often to extent that fails the system performance requirements. Therefore, class-AB power amplifiers or other variations are used with some suitable form of linearization schemes such as feedback, feedforward or analog or digital predistortion (DPD). In DPD power amplifier systems, the transfer characteristics of the amplifier are modeled by sampling the output of the PA and the inverse characteristics are calculated in a DSP processor. The digital baseband signal is multiplied by the inverse of PA nonlinear transfer characteristics, up-converted to RF frequencies and is applied to the PA input. With careful design of PA response, the DPD engines can correct the PA output distortion and achieve higher efficiencies.