Tests of FPDR90 IC for hybrid detector readout for high frame rate X-ray applications

We report on the high count rate and high frame rate measurements of a prototype IC called FPDR90 dedicated for readout of hybrid pixel semiconductor detectors used for X-ray imaging applications. The FPDR90 is designed in 90 nm CMOS technology and has dimensions of 4 mm × 4 mm. It´s main part is a matrix of 40 × 32 pixels with 100 μm × 100 μm pixel size. The chip work in single photon counting mode with two discriminators and two 16-bit ripple counters per pixel. The count rate per pixel depends on the effective CSA feedback resistance and can be set up to 6 Mcps per pixel. The FPDR90 can operate in continuous readout mode, with a zero dead time. Due to the architecture of digital blocks in pixel, one can select the number of readout bits from each counter from 1 to 16 bits. Because in the FPDR90 prototype only one data output is available, the frame rate is 9 kHz and 72 kHz for 16 bits and 1 bit readout from single pixel respectively (with nominal clock frequency of 200 MHz).