A CMOS-Based ISFET Chemical Imager With Auto-Calibration Capability

作者：Goh Clinton Z D^*; Georgiou Pantelis; Constandinou Timothy G; Prodromakis Themistoklis; Toumazou Christofer

来源：IEEE Sensors Journal, 2011, 11(12): 3253-3260.

DOI：10.1109/JSEN.2011.2155644

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

This paper presents a novel auto-calibration technique for eliminating sensor mismatch in CMOS-based chemical imagers. Designed using an 8 x 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-mu m 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.

• 出版日期2011-12