A 0.033-mm<inline-formula> <tex-math notation="LaTeX">$^{2}$</tex-math> </inline-formula> 21.5-aF to 114.9-aF Resolution Continuous-Time <inline-formula> <tex-math notation="LaTeX">$\Delta\Sigma$</tex-math> </inline-formula> Capacitance-to-Digital Converter Achieving Parasitic Capacitance Immunity Up to 480 pF

Hyeyeon Lee, Changuk Lee, Inhee Lee, Youngcheol Chae

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

This article presents a continuous-time (CT) delta&#x2013;sigma (<inline-formula> <tex-math notation="LaTeX">$\Delta\Sigma$</tex-math> </inline-formula>) capacitance-to-digital converter (CDC) intended for use in applications with high capacitance resolution (tens of aF), and a large parasitic capacitance <inline-formula> <tex-math notation="LaTeX">${C}_{P}$</tex-math> </inline-formula> (<inline-formula> <tex-math notation="LaTeX">$&gt;$</tex-math> </inline-formula>400 pF). It consists of a current conveyor (CC) front-end and a CT <inline-formula> <tex-math notation="LaTeX">$\Delta\Sigma$</tex-math> </inline-formula> modulator. The CC-based front-end isolates <inline-formula> <tex-math notation="LaTeX">${C}_{P}$</tex-math> </inline-formula> from the first integrator of the modulator, and the CC&#x2019;s output current is directly coupled to the CT <inline-formula> <tex-math notation="LaTeX">$\Delta\Sigma$</tex-math> </inline-formula> modulator. The CC uses a class-AB configuration, which enables to maintain energy efficiency and its capacitance resolution even with <inline-formula> <tex-math notation="LaTeX">${C}_{P}$</tex-math> </inline-formula>. The proposed CDC is fabricated in a 110-nm CMOS process and occupies only 0.033 mm<inline-formula> <tex-math notation="LaTeX">$^{2}$</tex-math> </inline-formula>. It achieves a capacitance resolution of 21.5&#x2013;59 aF with an input range of 0.2&#x2013;1.5 pF. This corresponds to an effective resolution of 14.3 bits in a conversion time of 1.2 ms, while drawing only 120 <inline-formula> <tex-math notation="LaTeX">$\mu$</tex-math> </inline-formula>W from a 1.5-V supply. It also achieves a capacitance resolution of 119.4 aF with <inline-formula> <tex-math notation="LaTeX">${C}_{P}$</tex-math> </inline-formula> of 480 pF, offering robust capacitance resolution with external noise interference (10 <inline-formula> <tex-math notation="LaTeX">${V}_\text{PP}$</tex-math> </inline-formula>).

Original languageEnglish
Pages (from-to)1-10
Number of pages10
JournalIEEE Journal of Solid-State Circuits
DOIs
Publication statusPublished - 2022 Oct 1

Bibliographical note

Publisher Copyright:
IEEE

All Science Journal Classification (ASJC) codes

  • Electrical and Electronic Engineering

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