A 1.2-V 165-W 0.29-mmMultibit Sigma-Delta ADC for Hearing Aids Using Nonlinear DACs and With Over 91 dB Dynamic-Range

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27 Citations (Scopus)

Abstract

This paper describes the design and experimental evaluation of a multibit Sigma-Delta$(Sigma Delta)mce_markernbsp;modulator$(Sigma Delta {rm M})$with enhanced dynamic range (DR) through the use of nonlinear digital-to-analog converters (DACs) in the feedback paths. This nonlinearity imposes a trade-off between DR and distortion, which is well suited to the intended hearing aid application. The modulator proposed here uses a fully-differential self-biased amplifier and a 4-bit quantizer based on fully dynamic comparators employing MOS parametric pre-amplification to improve both energy and area efficiencies. A test chip was fabricated in a 130 nm digital CMOS technology, which includes the proposed modulator with nonlinear DACs and a modulator with conventional linear DACs, for comparison purposes. The measured results show that the$Sigma Delta {rm M}$using nonlinear DACs achieves an enhancement of the DR around 8.4 dB (to 91.4 dB). Power dissipation and silicon area are about the same for the two cases. The performance achieved is comparable to that of the best reported multibit$Sigma Delta$ADCs, with the advantage of occupying less silicon area (7.5 times lower area when compared with the most energy efficient$Sigma Delta {rm M}$).
Original languageEnglish
Pages (from-to)376-385
JournalIeee Transactions On Biomedical Circuits And Systems
Volume7
Issue number3
DOIs
Publication statusPublished - Jun 2013

Keywords

  • Hearing aids
  • multibit
  • nonlinear digital-to-analog converter (DAC)
  • parametric amplification
  • self-biasing
  • sigma-delta modulator

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