A 0.18 $\mu {\rm m}$ Biosensor Front-End Based on $1/f$ Noise, Distortion Cancelation and Chopper Stabilization Techniques

This paper presents a novel sensor front-end circuit that addresses the issues of
$1/f$
noise and distortion in a unique way by using canceling techniques. The proposed front-end is a fully differential transimpedance amplifier (TIA) targeted for current mode electrochemical biosensing applications. In this paper, we discuss the architecture of this canceling based front-end and the optimization methods followed for achieving low noise, low distortion performance at minimum current consumption are presented. To validate the employed canceling based front-end, it has been realized in a 0.18
$\mu {\rm m}$
CMOS process and the characterization results are presented. The front-end has also been tested as part of a complete wireless sensing system and the cyclic voltammetry (CV) test results from electrochemical sensors are provided. Overall current consumption in the front-end is 50
$\mu {\rm A}$
while operating on a 1.8 V supply.