Embedded front-end for charge amplifier configuration with sub-threshold MOSFET continuous reset

The paper reports the considerations necessary to design state of the art front-end electronic devices integrated on silicon X-ray detectors to perform functional charge amplification. In particular it concentrates on the characteristics of a MOSFET feedback device operated in subthreshold mode to perform a continuous reset of the feedback capacitance with minimum added noise and maximum linearity. Details of the external microelectronic circuitry that complements the front-end devices are also given. The designed two-chip system aims to reach very high stability in charge-to-voltage conversion and to fulfil the requirements of the most advanced X-ray spectroscopy experiments.