A 30.3 fA/√Hz Biosensing Current Front-End With 139 dB Cross-Scale Dynamic Range

IEEE Trans Biomed Circuits Syst. 2021 Dec;15(6):1368-1379. doi: 10.1109/TBCAS.2021.3124197. Epub 2022 Feb 17.

Abstract

This paper presents an 8-channel array of low-noise (30.3 fA/√Hz) current sensing front-ends with on-chip microelectrode electrochemical sensors. The analog front-end (AFE) consists of a 1st-order continuous-time delta-sigma (CT ΔΣ) modulator that achieves 123 fA sensitivity over a 10 Hz bandwidth and 139 dB cross-scale dynamic range with a 2-bit programmable current reference. A digital predictor and tri-level pulse width modulated (PWM) current-steering DAC realize the equivalent performance of a multi-bit ΔΣ in an area- and power-efficient manner. The AFE consumes 50.3 µW and 0.11 mm2 per readout channel. The proposed platform was used to observe protein-ligand interactions in real-time using transient induced molecular electronic spectroscopy (TIMES), a label- and immobilization-free biosensing technique.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amplifiers, Electronic*
  • Biosensing Techniques*
  • Equipment Design
  • Heart Rate
  • Microelectrodes