A Low-Noise Weak Current Detection Amplifier for Wide Temperature Ranges

A low-noise weak current detection amplifier is proposed, featuring a transimpedance amplifier (TIA) with adjustable pseudo-resistance to provide high transimpedance gain. The amplifier's input is equipped with low-leakage electrostatic discharge (ESD) protection to achieve ultra-low input leakage, effectively addressing the leakage issues present in traditional ESD circuits. This paper meticulously analyzes the impact of integrating low-leakage ESD circuits on the stability and noise performance of the TIA system, and proposes viable solutions. Notably, the noise is effectively suppressed even at elevated temperatures. The prototype amplifier demonstrates an RMS integrated noise of 3.05 fA<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RMS</inf> within the circuit bandwidth, operating at a transimpedance gain of 100G and a temperature of 85°C.