A near-threshold cell-based all-digital PLL with hierarchical band-selection G-DCO for fast lock-in and low-power applications

Chia Wen Chang, Yuan Hua Chu, Shyh-Jye Jou

    Research output: Contribution to journalArticlepeer-review

    2 Scopus citations

    Abstract

    This paper presents a cell-based all-digital phase-locked loop (ADPLL) with hierarchical gated digitally controlled oscillator (GDCO) for low voltage operation, wide frequency range as well as lowpower consumption. In addition, a new time-domain hierarchical frequency estimation algorithm (HFEA) for frequency acquisition is proposed to estimate the output frequency in 1.5M F (M F = 3 in this paper) cycles and this fast lock-in time is suitable to the dynamic voltage frequency scaling (DVFS) systems. A hierarchical G-DCO is proposed to work at low supply voltage to reduce the power consumption and at the same time to achieve wide frequency range and precise frequency resolution. The core area of the proposed ADPLL is 0.02635 mm2. In near-threshold region (VDD = 0.36 V), the proposed ADPLL only dissipates 68.2 μW and has a rms period jitter of 1.25% UI at 60 MHz output clock frequency. Under 0.5 V VDD operation, the proposed ADPLL dissipates 404.2 μWat 400 MHz. The fast lock-in time of 4.489 μs and the low jitter performance below 0.5% UI at 400 MHz output clock frequency in the proposed ADPLL are suitable in event-driven or DVFS applications.

    Original languageEnglish
    Pages (from-to)882-891
    Number of pages10
    JournalIEICE Transactions on Electronics
    VolumeE98C
    Issue number8
    DOIs
    StatePublished - 1 Aug 2015

    Keywords

    • All-digital phase-locked loop
    • Fast lock-in
    • Hierarchical digitally controlled oscillators
    • Low jitter
    • Low power
    • Low voltage

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