A Class-D Tri-Phasing CMOS Power Amplifier with an Extended Marchand-Balun Power Combiner

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Researchers

Research units

  • Tampere University

Abstract

This article presents a power amplifier (PA) design, which consists of eight class-D PA units on a single 28-nm CMOS die and a coupled-line power combiner on printed circuit board. The PA utilizes tri-phasing modulation, which combines polar and outphasing components in a way that eliminates linearity-degrading effects of multilevel outphasing while maintaining the back off efficiency. Each PA unit contains a cascoded output stage with a 3.6-V supply voltage, and multilevel operation is enabled by ON/OFF logic circuitry. Our analysis shows that the choice of power-combiner type is vital for reducing PA supply and ground ripple and thus ensuring reliable operation. Accordingly, the power combiner is implemented with extended Marchand baluns, which consist of input transmission lines and coupled-line sections. Unlike the original Marchand balun, our new topology is feasible for implementation under the layout restrictions caused by the multiple-unit PA on a single die. Measurement results show the PA achieving a peak output power of 29.7 dBm with a 34.7% efficiency, and operation with aggregated Long Term Evolution (LTE) signals at 1.7-GHz carrier frequency is verified with bandwidths up to 100 MHz.

Details

Original languageEnglish
Article number8933356
Pages (from-to)1022-1034
Number of pages13
JournalIEEE Transactions on Microwave Theory and Techniques
Volume68
Issue number3
Publication statusPublished - 1 Mar 2020
MoE publication typeA1 Journal article-refereed

    Research areas

  • CMOS integrated circuits, Marchand balun, outphasing, power amplifiers (PA), power combiners, radio transmitters, tri-phasing

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