A 500-MHz Bandwidth 7.5-mVpp Ripple Power-Amplifier Supply Modulator for RF Polar Transmitters

Chul Kim, Chang Seok Chae, Young Sub Yuk, Chris M. Thomas, Yi Gyeong Kim, Jong Kee Kwon, Sohmyung Ha, Gert Cauwenberghs, Gyu Hyeong Cho

    Research output: Contribution to journalArticle

    Abstract

    The parallel combination of a switching and a linear amplifier in the supply modulator for RF power amplifiers (PAs) has the potential to enhance energy efficiency while achieving wider bandwidth and lower ripple output voltage. In this paper, a linear amplifier that features a buffered-switching Class-AB bias scheme is presented for the supply modulator in polar-transmitter structures achieving 500 MHz of small-signal 3-dB bandwidth at a 1.2-V supply. The linear amplifier absorbs and cancels up to 60 mA of ripple current from the switching amplifier. As such, the ripple in the output voltage of the hybrid linear-switching supply modulator is less than 7.5 mVpp. The switching amplifier provides most of the signal current for greatest efficiency owing to a proposed rail-to-rail current-sensing circuit. Current feedback in the switching amplifier achieves 1.68-MHz unity-gain bandwidth at 6-MHz switching frequency. Harmonic distortion in the output voltage of the supply modulator is below 40 dBc at 0.8 Vpp sinusoidal input up to 9 MHz. The peak efficiency is 87.7% for a 8.25- Ω load, while the maximum output power is 23.6 dBm for a 4.99- Ω load. The chip measures 1.35 mm2 in a 65-nm standard bulk CMOS process.

    LanguageEnglish (US)
    Pages1653-1665
    Number of pages13
    JournalIEEE Journal of Solid-State Circuits
    Volume53
    Issue number6
    DOIs
    StatePublished - Jun 1 2018

    Fingerprint

    Power amplifiers
    Modulators
    Transmitters
    Bandwidth
    Rails
    Electric potential
    Harmonic distortion
    Switching frequency
    Energy efficiency
    Feedback
    Networks (circuits)

    Keywords

    • Class-AB bias
    • current feedback
    • current sensing
    • envelope elimination and restoration
    • hybrid supply modulator (HSM)
    • open-loop gate driver polar transmitter
    • three-stage amplifier
    • wide bandwidth

    ASJC Scopus subject areas

    • Electrical and Electronic Engineering

    Cite this

    Kim, C., Chae, C. S., Yuk, Y. S., Thomas, C. M., Kim, Y. G., Kwon, J. K., ... Cho, G. H. (2018). A 500-MHz Bandwidth 7.5-mVpp Ripple Power-Amplifier Supply Modulator for RF Polar Transmitters. IEEE Journal of Solid-State Circuits, 53(6), 1653-1665. https://doi.org/10.1109/JSSC.2018.2804043

    A 500-MHz Bandwidth 7.5-mVpp Ripple Power-Amplifier Supply Modulator for RF Polar Transmitters. / Kim, Chul; Chae, Chang Seok; Yuk, Young Sub; Thomas, Chris M.; Kim, Yi Gyeong; Kwon, Jong Kee; Ha, Sohmyung; Cauwenberghs, Gert; Cho, Gyu Hyeong.

    In: IEEE Journal of Solid-State Circuits, Vol. 53, No. 6, 01.06.2018, p. 1653-1665.

    Research output: Contribution to journalArticle

    Kim, C, Chae, CS, Yuk, YS, Thomas, CM, Kim, YG, Kwon, JK, Ha, S, Cauwenberghs, G & Cho, GH 2018, 'A 500-MHz Bandwidth 7.5-mVpp Ripple Power-Amplifier Supply Modulator for RF Polar Transmitters' IEEE Journal of Solid-State Circuits, vol. 53, no. 6, pp. 1653-1665. https://doi.org/10.1109/JSSC.2018.2804043
    Kim, Chul ; Chae, Chang Seok ; Yuk, Young Sub ; Thomas, Chris M. ; Kim, Yi Gyeong ; Kwon, Jong Kee ; Ha, Sohmyung ; Cauwenberghs, Gert ; Cho, Gyu Hyeong. / A 500-MHz Bandwidth 7.5-mVpp Ripple Power-Amplifier Supply Modulator for RF Polar Transmitters. In: IEEE Journal of Solid-State Circuits. 2018 ; Vol. 53, No. 6. pp. 1653-1665.
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