Noise Analysis of Radiation Detector Charge Sensitive Amplifier Architectures

In this work, a detailed comparison of four equivalent charge-sensitive, folded-cascode amplifiers in terms of noise performance is presented. A couple of complementary structures, one with a noise-optimised input nMOSFET and the other with a noise-optimised input pMOSFET were designed in 0.35 μm CMOS process by Austria MicroSystems (AMS). Another couple of complementary structures consisting of a noise-optimised input npn with a pMOSFET cascode, and the respective structure having a pMOS as input device, were developed in a 0.35 μm SiGe BiCMOS process (AMS). The structures' comparison is performed through simulation, after careful selection of the parameters that remain constant in all four variations.