APDROC: A Front-End ASIC for APD Array Detector in High Time-Resolved Synchrotron Experiments

A front-end application-specified integrated circuit (ASIC) chip has been developed for avalanche-photodiode (APD) array detectors in X-ray time-resolved experiments. The chip has eight channels. Each channel consists of a preamplifier, a voltage discriminator and an open-drain output driver. A prototype chip has been designed and fabricated by a 0.13-μm CMOS technology with a chip size of 2.4 mm × 1.1 mm. The electrical characterizations of the chip demonstrate a good time resolution (rms) on the output pulse leading edge, with the test result better than 34.4 ps for high input signal charges (>100 fC) and better than 98 ps for low input signal charges (30-100 fC), while keeping a high count rate of 3.3 × 10
⁸
/s per channel.