Low-noise and high-speed trans-impedance amplifier for nanopore sensor
Shaoxi Fang, Bohua Yin, Wanyi Xie, Shixuan He, Liyuan Liang, Peng Tang, Rong Tian, Ting Weng, Jiahu Yuan, Deqiang Wang
Abstract
The small current detection circuit is the core component of the accurate detection of the nanopore sensor. In this paper, a compact, low-noise, and high-speed trans-impedance amplifier is built for the nanopore detection system. The amplifier consists of two amplification stages. The first stage performs low-noise trans-impedance amplification by using ADA4530-1, which is a high-performance FET operational amplifier, and a high-ohm feedback resistor of 1 GΩ. The high pass shelf filter in the second stage recovers the higher frequency above the 3 dB cutoff in the first stage to extend the maximum bandwidth up to 50 kHz. The amplifier shows a low noise below sub-2 pA rms when tuned to have a bandwidth of around 5 kHz. It also guarantees a stable frequency response in the nanopore sensor.