WiMAX Power Amplifier Features High Linearity, Efficiency

Designed for mobile WiMAX terminals, the ADL5570 is a high-linearity power amplifier (PA) optimized for operation in the 2.3- to 2.4-GHz band, with good performance across frequency bands from 2.5 to 2.7 GHz. Compared to other WiMAX PAs, the ADL5570 consumes half the current and offers an industry-leading power-added efficiency of more than 20%, according to Analog Devices Inc. The lower power consumption limits the need for heatsinks, increases system reliability, and reduces size and cost. The amplifier’s output 1-dB compression point of 31 dBm allows it to operate in the linear region at output power levels of up to 26 dB—at 2.35 GHz with a 3.5-V supply—while maintaining an error vector magnitude of less than 3%. A gain of 29 dB allows the amplifier to be used with a wide variety of transceivers.

Operating with a single 3.2- to 5.5-V supply, the ADL5570 consumes 250 mA rms. A low-power mode is also available for operation at levels less than 10 dBm, with optimized operating and quiescent currents of 100 mA and 70 mA, respectively. Also available is a standby mode, which reduces the quiescent current to 10 mA and is useful when a time-division duplex terminal is receiving data. The device comes in a 16-pin 4- by 4-mm lead-frame chip-scale package. Operating range is −40°C to 85°C.