A 128-Channel CMOS Charge Readout ASIC for Flat-Panel X-Ray Detectors

A CMOS charge readout ASIC (SD7110) for flat-panel X-ray detectors was designed and tested. This ASIC contains 128 readout channels, with each channel consisting of a charge sensitive amplifier, a correlated double sampler, and a track-and-hold circuit. Channel outputs are read out via a 128:1 analog multiplexer and fed into an external 16-bit A/D converter. Conversion gain can be selected from 0.25 V/pC to 8 V/pC. The ASIC operates using a +5.0 V single power supply, with power dissipation of 1.8 mW/channel. The equivalent noise charge (ENC) measured was 400 + 18.9 e-/pF.