A 9-bit 100MS/s SAR ADC with digitally assisted background calibration

Xiaolei Zhu, Yanfei Chen, Sanroku Tsukamoto, Tadahiro Kuroda

    Research output: Contribution to journalArticlepeer-review

    2 Citations (Scopus)


    The performance of successive approximation register (SAR) analog-to-digital converter (ADC) is well balanced between power and speed compare to the conventional flash or pipeline architecture. The nonlinearities suffer from the CDAC mismatch and comparator offset degrades SAR ADC performance in terms of DNL and INL. An on chip histogram-based digitally assisted background calibration technique is proposed to cancel and relax the aforesaid nonlinearities. The calibration is performed using the input signal, watching the digital codes in the specified vicinity of the decision boundaries, and feeding back to control the compensation capacitor periodically. The calibration does not require special calibration signal or additional analog hardware which is simple and amenable to hardware or software implementations. A 9-bit SAR ADC with split CDAC has been implemented in a 65 nm CMOS technology and it achieves a peak SNDR of 50.81 dB and consumes 1.34mW from a 1.2-V supply. +0.4/-0.4 LSB DNL and +0.5/-0.7 LSB INL are achieved after calibration. The ADC has input capacitance of 180 fF and occupies an area of 0.1 ×0.13mm2.

    Original languageEnglish
    Pages (from-to)1026-1034
    Number of pages9
    JournalIEICE Transactions on Electronics
    Issue number6
    Publication statusPublished - 2012 Jun


    • ADC
    • Charge redistribution
    • Digital background calibration
    • Nonlinearity
    • Split capacitor DAC
    • Successive approximation

    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Electrical and Electronic Engineering


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