Low-Noise Current Sensing System for Nanopore

A high-gain low-noise current signal detection system ASIC for biosensors

Abstract

In this paper, a high-gain low-noise current signal detection system ASIC for biosensors is proposed. A resistive feedback transimpedance amplifier (TIA) was used for the biosensor that required a bias voltage, and the structure was designed to stably display the current flowing through the biosensor on the self-made graphical user interface (GUI) even when the bias voltage was changed. This paper introduces a proposed technique for the automatic calibration of current between sensors in an integrated biosensor featuring an array structure. The method involves controlling the gate bias voltage of the sensor to achieve the desired calibration. To optimize the circuit design, pseudo-resistors are employed, allowing for the implementation of a high-gain MOSFET resistor while minimizing the required area. Additionally, noise reduction is achieved through the utilization of a chopper technique. By using pseudo-resistors, a large resistor for high gain can be implemented as a MOSFET to reduce area, and noise is reduced using a chopper technique. The sensing circuit, specifically designed for biosensors, demonstrates exceptional performance with a gain of 160 dBΩ and input-referred noise of 4 pArms. The circuit is realized using 130 nm CMOS process technology, showcasing its feasibility in practical biosensing applications. The chip area is 17mm² and the power consumption is 10mW.