A 0.35μm Low-Noise Stable Charge Sensitive Amplifier for Silicon Detectors Applications

The Charge Sensitive Amplifier (CSA) is the key module of the front-end electronics of various types of Silicon detectors and most radiation detection systems. High gain, stability, and low input noise are the major concerns of a typical CSA circuit in order to achieve amplified susceptible input charge (current) for further processing. To design such a low-noise, stable, and low power dissipation solution, a CSA is required to be realized a complementary metal-oxide-semiconductor (CMOS) technology with a compact design. This research reports a low-noise highly stabile CSA design considerations for Silicon detectors applications, which has been designed and validated in TSMC 0.35um CMOS process.  In a typical CSA design, the detector capacitance and the input transistor’s width are the most dominating parameters for achieving low noise performance. Therefore, the Equivalent Noise Charge (ENC) with respect to those parameters has been optimized, for a set of detector capacitance from 0.2pF – 2pF. However, the parallel noise of the feedback was removed by adopting a voltage-controlled NMOS resistor, which in turn helped to achieve high stability of the circuit. The simulation results provided a baseline gain of 9.92mV/fC and show that ENC was found to be 42.5e – with 3.72 e – /pF noise slope. The Corner frequency exhibited by the CSA is 1.023GHz and the output magnitude was controlled at -56.8dB; it dissipates 0.23mW from with a single voltage supply of 3.3V with an active die area of 0.0049 mm 2 .