Advances in Voltage-Controlled-Oscillator-Based ΔΣ ADCs

Shaolan LI  Arindam SANYAL  Kyoungtae LEE  Yeonam YOON  Xiyuan TANG  Yi ZHONG  Kareem RAGAB  Nan SUN  

IEICE TRANSACTIONS on Electronics   Vol.E102-C    No.7    pp.509-519
Publication Date: 2019/07/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.2018CTI0001
Type of Manuscript: Special Section INVITED PAPER (Special Section on Analog Circuits and Their Application Technologies)
voltage-controlled-oscillator,  ring oscillator,  analog-to-digital converter,  time-domain signal processing,  VCO-based ADC,  ΔΣ ADC,  

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Ring voltage-controlled-oscillators (VCOs) are increasingly being used to design ΔΣ ADCs. They have the merits of simple, highly digital and low-voltage tolerant, making them attractive alternatives for the classic scaling-unfriendly operational-amplifier-based methodology. This paper aims to provide a summary on the advancement of VCO-based ΔΣ ADCs. The scope of this paper includes the basics and motivations behind the VCO-based ADCs, followed by a survey covering a wide range of architectures and circuit techniques in both continuous-time (CT) and discrete-time (DT) implementation, and will discuss the key insights behind the contributions and drawbacks of these architectures.