A MATLAB-based Method for Designing High-Gain Resonant Transimpedance Amplifiers

In this paper, we propose a novel efficient method for the design of high-gain resonant transimpedance amplifiers (TIAs) usingMATLAB. The procedure provides the designer with an effective tool, useful to explore the effects of different device parameter combinations in complex network topologies used in several application fields. We applied this method to improve the detection capability of a previously designed chlorophyll-A (Chl-A) sensor, in order to in-vivo assess the seawater quality. By exploiting the interesting bandpass behavior exhibited by a T feedback network, we were able to redesign the resonant TIA stage of a low-cost lock-in amplifier working at 1 kHz, easily increasing the gain by a factor of 100, and reaching an overall gain of 216 dB while reducing the detectivity to almost 500 fA. Moreover, the proposed analysis provides the optimal circuit parameter values for a wide working frequency range without further numerical optimization, giving an interesting perspective of its potential use in those telecommunication applications where high sensitivity is required.