Integrated front-end readout electronics and analog filtering strategies for DEPFETs with special functionalities

DEPFET is a natural building block for pixel sensors as it comprises the properties of detector, amplifier and storage cell in a simple structure. DEPFET devices have been designed and fabricated with different topologies and their properties can be tailored according to the needs of different applications. In order to fully exploit the unique characteristics of the different DEPFETs, a suitable front-end integrated readout electronics and an ad-hoc filtering scheme must be adopted for every individual type of device and experiment. This work will focus on the front-end readout electronics for the Repetitive-Non-Destructive-Readout-DEPFET (RNDR-DEPFET) and for the Non-Linear DEPFET developed for XFEL in Hamburg. We present an optimized circuit and an optimized readout scheme that will allow reading out the two DEPFETS of the RNDR device simultaneously, reducing in this way the readout time of a factor 2. The proposed readout scheme constitutes the first step towards the development of a matrix of DEPFETs which can be operated in a complete parallel readout with a frame rate of some kHz. This readout speed, combined with the extremely low noise achieved, makes this system attractive for high-speed optical astronomy and adaptive optics. The DEPFET pixel array proposed for XFEL requires full parallel readout with a signal processing time not longer than 200ns, up to 10000 photons @1keV per-pixel and single photon resolution @1keV. Due to the very strict area constraints, a front-end readout electronics that provides amplification and Correlated Double Sampling in one single stage has been designed in a 130nm CMOS technology. The key properties of this circuit together with the expected noise performance will be discussed.