A multi-channel charge readout IC with offset calibration for X-ray industrial inspection

A multi-channel charge readout integrated circuit (IC) which converts detector charge to analog voltage with offset calibration for X-ray industrial inspection is described. The charge readout IC provides 64 channels of circuit having a max dynamic range of 14 bit and is comprised of charge amplifier gain control, timing generator, shift register chain, charge amplifier array, sample/hold (S/H) stage amplifier and driver etc. It was fabricated using 0.8 um standard CMOS process, and occupies a die area of 3.1 mm × 10.9 mm. It operates at 4 MHz, consumes 45 mW from 5 V supply and 3.5 V as reference, and has a demonstrated output noise performance of 600 uV_rms on 0.5 pF of charge amplifier gain capacitance and 33 pF of photodiode (PD) terminal capacitance.