A CMOS readout chip for pixel detectors

In this paper a CMOS readout chip is presented to be used with pixel detectors. The chip architecture consists of an array of mixed analog-digital channels; each channel is composed of a low-noise charge integrator, an analog discriminator with an external threshold, and a digital counter, all synchronised by a global distributed clock. A prototype chip has been realised to be coupled with GaAs pixel detectors for digital mammography applications. The chip has been tested, and the results show a good matching with the expected performances, proving the validity of the architecture.