• 08759916

    Accepted author manuscript, 940 KB, PDF document


This brief proposes a successive approximation register (SAR) analog-to-digital converter (ADC) whose readout speed is improved by 33%, through applying a digital error correction (DEC) method, compared to an alternative without using the DEC technique. The proposed addition-only DEC alleviates the ADC's incomplete settling errors, hence improving conversion rate while maintaining accuracy. It is based on a binary bridged SAR architecture with 4 redundant capacitors and conversion cycles, which ensure the ADC's linearity of 10 bit within a 5 bit accuracy's settling time. The proposed SAR keeps the same straightforward timing diagram as that in a conventional SAR ADC, incurring no offset to the ADC. Measurement results of 15 columns of SAR ADCs, sampling at 5 MS/s on the same CMOS image sensor (CIS) chip, show integral nonlinearity (INL) around 3 LSB (1LSB = 1 mV), when sampling at 5 MHz, after a proposed swift digital background calibration that incurs no additional hardware complexity. The CIS array read out by the proposed column-level SAR ADCs is measured reasonable photoelectron transfer characteristics.

Original languageEnglish
Article number8759916
Pages (from-to)984 - 988
Number of pages5
JournalIEEE Transactions on Circuits and Systems II: Express Briefs
Issue number6
Publication statusPublished - 2020

    Research areas

  • ADC, analog-to-digital converter, CMOS image sensor, DEC, digital background calibration, digital error correction, SAR, successive approximation register

ID: 68328743