High-efficiency WCDMA envelope tracking base-station amplifier implemented with GaAs HVHBTs

Jinseong Jeong, Donald F. Kimball, Myoungbo Kwak, Paul Draxler, Chin Hsia, Craig Steinbeiser, Thomas Landon, Oleh Krutko, Lawrence E. Larson, Peter M. Asbeck

Research output: Contribution to journalArticlepeer-review

75 Scopus citations

Abstract

A record high-performance GaAs high-voltage HBT (HVHBT)-based WCDMA base-station power amplifier is presented, which uses an envelope tracking bias system to achieve high efficiency and linearity. A wideband envelope amplifier provides dynamic collector supply biasing to the RF stage. A digital pre-distortion technique is employed to satisfy the linearity specifications of WCDMA. The measured overall power-added efficiency reached 58% with a normalized root-mean-square (RMS) error of 2.9% and an adjacent channel leakage ratio (ACLR) of -49 dBc at 5-MHz offset at an average output power of 42 W and a gain of 10.3 dB for a single carrier WCDMA signal with 6.6-dB peak-to-average power ratio. A memory mitigation algorithm further improves the linearity, resulting in an ACLR of -70 dBc and a normalized RMS error of 0.3%. Measurements were made to quantify separately the efficiency contributions of the HVHBT-based RF stage, and of the envelope amplifier. The measurements show that the RF stage operates at collector efficiency above 85% over most of the instantaneous power range of the WCDMA signal. This remarkably high efficiency is the result of low on-resistance and low (and nearly voltage independent) output capacitance of the HVHBT.

Original languageEnglish
Article number5
Pages (from-to)2629-2639
Number of pages11
JournalIEEE Journal of Solid-State Circuits
Volume44
Issue number10
DOIs
StatePublished - Oct 2009

Keywords

  • Base-station power amplifier
  • Digital pre-distortion
  • Efficiency
  • Envelope tracking
  • GaAs HVHBT
  • Linearity
  • Memory mitigation
  • Peak-to-average power ratio
  • WCDMA
  • WiMAX

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