A hybrid SAR-VCO ΔΣ ADC with first-order noise shaping

Arindam Sanyal, Kareem Ragab, Long Chen, T. R. Viswanathan, Shouli Yan, Nan Sun

Research output: Chapter in Book/Report/Conference proceedingConference contribution

24 Scopus citations

Abstract

A scaling-friendly, hybrid, two-stage ΔΣ ADC with a 5-bit SAR as first stage and a VCO as second stage is presented in this work. Since the VCO can provide fine quantization for small signals in the time-domain, it is used to directly quantize the SAR residue without OTA-based residue amplification. Also, having a small input swing obviates the need for VCO non-linearity calibration. The VCO phase overflow problem is solved by using a counter to record the number of overflows, thus allowing a variable sampling rate. Since the VCO phase and counter are never reset, the VCO's first-order noise-shaping capability is retained. A prototype ADC in an 180 nm process achieves 73 dB SNDR over 2.2 MHz bandwidth and consumes 5 mW from a 1.8V supply while sampling at 35 MHz.

Original languageEnglish (US)
Title of host publicationProceedings of the IEEE 2014 Custom Integrated Circuits Conference, CICC 2014
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Electronic)9781479932863
DOIs
StatePublished - Nov 4 2014
Externally publishedYes
Event36th Annual Custom Integrated Circuits Conference - The Showcase for Integrated Circuit Design in the Heart of Silicon Valley, CICC 2014 - San Jose, United States
Duration: Sep 15 2014Sep 17 2014

Publication series

NameProceedings of the IEEE 2014 Custom Integrated Circuits Conference, CICC 2014

Other

Other36th Annual Custom Integrated Circuits Conference - The Showcase for Integrated Circuit Design in the Heart of Silicon Valley, CICC 2014
Country/TerritoryUnited States
CitySan Jose
Period9/15/149/17/14

Keywords

  • analog to digital converters (ADC)
  • noise shaping
  • successive approximation register (SAR)
  • two stage ADC
  • voltage controlled oscillator (VCO)

ASJC Scopus subject areas

  • Electrical and Electronic Engineering

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