2-way Doherty amplifier with BLF888A

NXP BLF888A

Application Note AN11325
November 2013

This document gives a description and measurement results of a 2-way Doherty amplifier using 2 BLF888A UHF LDMOS transistors.

The document introduces a narrowband 2-way Doherty amplifier (test) demo board. Using the board together with modeling software and measuring test equipment, details of amplifier designs for three DBV-T frequencies are given.

The process of the designs and the measurements and modeling results are also given. The test board comprises one PCB containing the broadband main and peaking amplifiers, and a second PCB containing the Doherty combiner. The main and peaking amplifiers each uses a BLF888A UHF LDMOS transistor, together with associated components. The broadband amplifier blocks cover the whole UHF band.

Amplifier bandwidth and base frequency is dependent on the Doherty combiner design. Several narrowband design versions of the Doherty combiner PCB can be built and interchanged on the demo board to determine the required amplifier frequency.

The amplifier has minimum output power of 200 W average (DBV-T) and approximately 50 MHz of bandwidth (depending on the center frequency).

Download Application Note AN11325 (588 Kb)

Doherty amplifier demo board
Doherty amplifier demo board

You may have to register before you can post comments and get full access to forum.
EMS supplier