An ultrafast front-end ASIC for APD array detectors in X-ray time-resolved experiments

An ultrafast front-end ASIC chip has been developed for APD array detectors in X-ray time-resolved experiments. The chip has five channels: four complete channels and one test channel with an analog output. Each complete channel consists of a preamplifier, a voltage discriminator and an open-drain output driver. A prototype chip has been designed and fabricated using 0.13 mu m CMOS technology with a chip size of 1.3 mm x 1.9 mm. The electrical characterizations of the circuit demonstrate a very good intrinsic time resolution (rms) on the output pulse leading edge, with the test result better than 30 ps for high input signal charges (> 75 fC) and better than 100 ps for low input signal charges (30-75 fC), while keeping a low power consumption of 5 mW per complete channel.