A 29dBm linear output power amplifier with 21.3% efficiency for 700MHz-band 3GPP LTE OFDMA applications

This paper describes the design and realization of a single-chip, 5V supply linear power amplifier for the 3 GPP Long-Term Evolution (LTE) applications in the 700 MHz band. When tested using a 10 MHz modulation bandwidth OFDMA signal with 64-QAM modulation, the amplifier achieves 29 dBm power with less than 2.5% EVM at efficiencies above 21% across the downlink band. Nominal gain is 33 dB. Also included on-chip is a CMOS-compatible pin for 15dB attenuation gain control and a buffered RF detector. The amplifier is capable of less than 15uA leakage current in OFF mode. Low-supply voltage operation with a 3.3V supply is also possible with 25.5 dBm of linear output power. The amplifier is fabricated using a proprietary 0.25 um E-mode pHEMT technology and is housed in a 5 mm × 5 mm QFN plastic package.