A 900 MHz, 500 W Doherty Power Amplifier Using Optimized Output Matched Si LDMOS Power Transistors

The RF performance of a 500 W, 900 MHz Doherty amplifier using a new input and output pre-matched power transistor featuring Freescale Semiconductor´s latest generation 900 MHz LDMOS technology is demonstrated. The amplifier achieves 49.5 dBm power and 41% efficiency at -55 dBc linearity with memory-polynomial based digital predistortion across the 869-894 MHz band with a 7.5 dB composite PAR 2-carier 3GPP signal. The design of the amplifier is described, as is the design and RF performance of the transistor, which is capable of 260 W CW P1dB and 300 W pulsed P1dB over 60 MHz of bandwidth in class AB operation.