Active Feedbacks Comparative Analysis for Charge Sensitive Amplifiers Designed in CMOS 40 nm

In this paper we present a comparative analysis of active feedback circuits dedicated to charge sensitive amplifiers (CSA) used in X-ray imaging systems. This work is motivated by the fact there are many papers discussing advantages and disadvantages of using particular CSA feedback but non of them are done in the same process which is very crucial. The presented design, prototype recording channels fabrication employing two the most competing solutions, and their further measurement results may therefore help one in choosing the most suitable feedback for a particular application. The presented circuits are designed in CMOS 40 nm process and are compared in terms of noise contribution, power consumption, area occupation, ability to minimize detectors leakage current, and also CSA stability.