Title :
CMOS transimpedance amplifier for biosensor signal acquisition
Author :
Ibrahim, Mark M. R. ; Levine, P.M.
Author_Institution :
Dept. of Electr. & Comput. Eng., Univ. of Waterloo, Waterloo, ON, Canada
Abstract :
We present a 1-GΩ CMOS transimpedance amplifier (TIA) suitable for processing sub-nA-level currents in electrochemical biosensor signal-acquisition circuits. Use of a two-stage active transconductor provides resistive feedback in place of a single large-area linear resistor. We engineer the TIA feedback loop to suppress output offset caused by dc input leakage currents of ±0.9 nA. We also implement a mechanism to tune the low-frequency cutoff of the TIA from 0.7 Hz to 500 Hz which permits operation under variable environmental conditions. We report simulated and experimental results from our custom TIA fabricated in a 3.3-V 0.35-μm CMOS process.
Keywords :
CMOS integrated circuits; bioelectric phenomena; biomedical measurement; biosensors; electrochemical sensors; operational amplifiers; resistors; signal processing equipment; CMOS process; CMOS transimpedance amplifier; TIA feedback loop; biosensor signal acquisition; custom TIA; dc input leakage currents; electrochemical biosensor signal-acquisition circuits; frequency 137 Hz to 500 Hz; low-frequency cutoff; output offset; resistance 1 Gohm; resistive feedback; single large-area linear resistor; sub-nA-level current processing; two-stage active transconductor; variable environmental conditions; voltage 3.3 V; Biosensors; CMOS integrated circuits; Current measurement; Gain; Noise; Resistors; Semiconductor device measurement;
Conference_Titel :
Circuits and Systems (ISCAS), 2014 IEEE International Symposium on
Conference_Location :
Melbourne VIC
Print_ISBN :
978-1-4799-3431-7
DOI :
10.1109/ISCAS.2014.6865056
