High linearity 32-channel CMOS X-ray readout integrated circuit

A new high linearity 32-channel X-ray readout integrated circuit (ROIC) is proposed in this paper. This ROIC has integrated analog circuit and digital circuit on the wafer. The analog circuit picked up the weak current signal from the detector, which includes low power charge sensitive amplifier (CSA), sample and hold circuit, and output buffer. The digital circuit generate control signal which the analog circuit needs. All 32 channels share one common current output buffer to drive a load resistor. With maximum 500pF detector parasitic capacitor (Cd), the linearity is about 99.93%. This 32-channel X-ray ROIC is also features with selectable gains, LVDS protocol compatible, selectable integration modes, selectable read out directions. 32-channel ROIC has been designed and a single-channel test chip is being fabricated with 0.5 μm 2P3M process.