MASc seminar - Mark Ibrahim

Friday, December 20, 2013 10:00 am - 10:00 am EST (GMT -05:00)


Mark Ibrahim


CMOS Transimpedance Amplifier for Biosensor Signal Acquisition


Levine, Peter M.


A 1-GO CMOS transimpedance amplifier (TIA) suitable for processing sub-nA-level currents in electrochemical biosensor signal-acquisition circuits is presented. Use of a two-stage active transconductor provides resistive feedback in place of a large-area linear resistor. The TIA feedback loop is engineered to suppress output offset caused by dc input leakage currents of ±0.9 nA. A mechanism to tune the low-frequency cutoff of the TIA from 0.7 Hz to 500 Hz is implemented which permits operation under variable environmental conditions. Simulated and experimental results from a custom TIA fabricated in a 3.3-V 0.35-µm CMOS process are presented.