A CMOS-based ISFET chemical imager with auto-calibration capability

Clinton Z.D. Goh*, Pantelis Georgiou, Timothy G. Constandinou, Themistoklis Prodromakis, Christofer Toumazou

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

This paper presents a novel auto-calibration technique for eliminating sensor mismatch in CMOS-based chemical imagers. Designed using an 8×8 array comprising of pH-sensitive ion-sensitive field-effect transistors (ISFETs), the chemical imager is capable of implementing a gradient-based calibration algorithm by biasing programmable-gate (PG) ISFETs at a common operating point when exposed to a solution of homogenous pH. The system was fabricated in a typical 0.35-μm CMOS technology and demonstrated a fast rate of convergence (500 ms per iteration) while a convergence accuracy of 45 mV on a gain of 10 (0.5% relative standard error and 2% pixel-to-pixel variation) was achieved. A maximum pH sensitivity of 57 mV/pH is also reported.

Original languageEnglish
Article number5770163
Pages (from-to)3253-3260
Number of pages8
JournalIEEE Sensors Journal
Volume11
Issue number12
DOIs
Publication statusPublished - 19 May 2011

Keywords / Materials (for Non-textual outputs)

  • Array
  • calibration
  • chemical imager
  • ion-sensitive field-effect transistor (ISFET)
  • lab-on-chip

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