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Circuits, Systems, and Signal Processing

, Volume 36, Issue 3, pp 1150–1168 | Cite as

A Flash ADC Tolerant to High Offset Voltage Comparators

  • António Couto-Pinto
  • Jorge R. Fernandes
  • Moisés Piedade
  • Manuel M. Silva
Article
  • 256 Downloads

Abstract

A conventional flash analog-to-digital converter (ADC) with a Wallace tree encoder ensures monotonicity and avoids missing codes, but still requires comparators with low offset voltage, which implies high area and power consumption. In this paper, we extend the purpose of this flash implementation, to allow the comparators to have extremely high offset voltages. This leads to a new approach toward the design of a flash ADC that does not require any type of calibration, allow easy porting among technologies and benefits from scaling. A statistical study is presented to demonstrate the effectiveness of the new method, and a modification is proposed to ensure full-range operation. It is shown that a proposed N-bit ADC has a performance equivalent to an \((N-m)\)-bit conventional flash ADC, with considerable gains in area and power consumption, with less design effort. The design flow of the OST ADC, with the necessary steps, is presented. A circuit, employing minimum dimension transistors, was fabricated in 0.13-\({\upmu }\hbox {m}\) CMOS and used as a proof of concept for the ADCs proposed here.

Keywords

Analog–digital conversion Flash ADC Wallace tree Stochastic errors Offset voltage 

Notes

Acknowledgments

This work has been supported by FCT, Fundação para a Ciência e a Tecnologia (Portugal), under projects PEst-OE/EEI/LA0021/2013 and DISRUPTIVE (EXCL/EEI-ELC/0261/2012).

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Copyright information

© Springer Science+Business Media New York 2016

Authors and Affiliations

  1. 1.INESC-ID-Lisboa, Department of Electronics, Telecommunications and Computers EngineeringInstituto Superior de Engenharia de LisboaLisbonPortugal
  2. 2.INESC-ID-Lisboa, Instituto Superior TécnicoUniversidade de LisboaLisbonPortugal

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