SiGe BiCMOS CSA-shaper radiation detection front end: Noise performance and noise modelling

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 -extended analysis regarding SiGe BiCMOS radiation detection folded cascode based Charge pre-amplifiers is presented and selection criteria are suggested in relation to the detector capacitance value. In addition, NPN HBT noise modelling analysis is also performed in order to extract conclusions about the related noise sources and to investigate the capability for extra noise reduction.