Preamplifier topology for fluctuation enhanced sensing

Fluctuation Enhanced Sensing is a well known technique, based on noise measurements, to improve sensitivity and selectivity for chemical/biological sensing. Trans-impedance amplifiers (TIAs) are the natural choice as front-end for the measurement of the low frequency noise (LFN) generated by the sensor. In this work we propose a low-noise TIA topology which allows maintaining a large bandwidth also in the case of low impedance sources, e.g. large-capacitance metal-oxide-semiconductor gas sensors, without any significant degradation of the LFN performances. AC and NOISE circuit simulations are used to demonstrate the validity of the proposed approach.