<title>Two approaches to hybrid x-ray pixel array readout</title>

We have designed two different X-ray pixel array readout Integrated Circuits for silicon pixel detectors operating between 4 keV and 25 keV. The first allows full readout of the deposited charge for each X-ray photon and is intended for imaging X-ray spectroscopy. The second is a photon counting device capable of very high rates (1 MHz per pixel) but without energy resolution. This paper compares the architectures of these two detectors and presents experimental data from complete bump-bonded devices. These detectors have many applications from X-ray diffraction to material inspection and satellite based X-ray imaging.