VELA: the CMOS circuit based on fast current read-out for X-ray Spectroscopy with DePMOS

DePMOS based Active Pixel Sensor (APS) matrix is a new detector concept for X-ray imaging spectroscopy applications. This type of X-ray detectors can provide excellent energy resolution and high-speed readout. Both these features and the advantage of random pixel accessibility can fulfill the requirements of new space missions, like the XEUS Wide Field Imager. In a matrix arrangement, each pixel must be read out by a time variant filter, so a new readout mechanism and a proper multi-channel integrated shaping amplifier are needed. Finally, to operate at such a reduced processing time (e.g. 4 mus per line) DePMOS transistor can not be operated in the classical source follower configuration, because this results in a long settling time; so challenging design of full-custom multi-channel readout electronic has to be considered. We propose a new faster readout concept, which is based on the drain current readout.