Machine-Learning Based Nonlinerity Correction for Coarse-Fine SAR-TDC Hybrid ADC

Hao Deng, Qingjun Fan, Runxi Zhang, Jinghong Chen

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

15 Scopus citations

Abstract

This paper presents a backend machine learningbased nonlinearity calibration scheme for a coarse-fine two stage SAR-TDC hybrid ADC. Different from conventional approaches, the machine learning-based nonlinearity calibration scheme avoids the on-chip pseudonumber (PN) generator or complex, specific matrix operations in the digital domain backend process. The scheme utilizes a two-layer neural network to extract and compensate the bit-weight error caused by circuit nonlinearities such as inter-stage gain error or time-to-digital converter (TDC) delay cell mismatch. The neural network uses the ADC DNL and INL testing results as training data, thus avoiding additional reference channel or a split ADC structure. A 10-bit 500 MS/s coarse-fine SAR-TDC ADC is designed in 22nm FDSOI technology to validate the scheme. The simulation results show the ADC achieves an SNDR of 57 dB, SFDR of 71.3 dB, and an ENOB of 9.18 bits, corresponding to a Walden FOM of 5.2 fJ/conv.-step after backend nonlinearity calibration.

Original languageEnglish
Title of host publication2020 IEEE 63rd International Midwest Symposium on Circuits and Systems, MWSCAS 2020 - Proceedings
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages265-268
Number of pages4
ISBN (Electronic)9781538629161
DOIs
StatePublished - Aug 2020
Event63rd IEEE International Midwest Symposium on Circuits and Systems, MWSCAS 2020 - Springfield, United States
Duration: 9 Aug 202012 Aug 2020

Publication series

NameMidwest Symposium on Circuits and Systems
Volume2020-August
ISSN (Print)1548-3746

Conference

Conference63rd IEEE International Midwest Symposium on Circuits and Systems, MWSCAS 2020
Country/TerritoryUnited States
CitySpringfield
Period9/08/2012/08/20

Keywords

  • Coarse-fine ADC architecture
  • Machine learning-based nonlinearity correction
  • SAR ADC
  • Subrange TDC

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