GaN PA Supports 3.5-3.7 GHz Small Cell Applications Using Digital Predistortion

To address the needs of small-cell designers, Cree has introduced the CDPA35045 asymmetric Doherty power amplifier (PA) reference design for the 3.5 to 3.7 GHz band. This band is an additional spectrum space intended to complement small-cell technology by providing increased wireless system capacity for both licensed wireless carrier services and unlicensed public use, such as WiFi.

Providing 10W average output power and what is claimed to be excellent pre-distortion (DPD) correctability, the proven Doherty PA design utilizes Cree's 30 W CGHV27030S and 15 W CGHV27015S GaN high-electron-mobility transistor (HEMT) devices, which can operate with either 50 V or 28 V drain supplies and enable enhanced design flexibility for telecoms, wideband tactical radio, and radar applications spanning low frequencies to 6 GHz.

The CDPA35045 was evaluated by engineers at Xilinx in a 3.5 GHz test radio platform that implemented Xilinx CFR and DPD SmartCORE IP on a Xilinx ZC706 evaluation board featuring the firm's Zynq 7Z045 all-programmable system-on-chip (APSoC) as the processing engine. The evaluation proved that this combination of Xilinx's Zynq APSoC devices and Cree's GaN devices results in highly efficient, low-cost, and low-power products that enable full flexibility of control processing and the radio signal.

Consequently, the Cree CDPA35045 asymmetric Doherty PA combined with Xilinx radio signal processing IP is an effective solution for small-cell implementation in the 3.5 to 3.7 GHz wireless band. This combination provides base-station designers with a proven design that supports the development of new small-cell wireless infrastructure equipment, significantly reducing design time and enabling faster product time to market.