Waveform-Sampling Front-End ASIC for 3-D Position-Sensitive Detectors

In this article, a waveform-sampling front-end application-specific integrated circuit (ASIC) for 3-D position-sensitive detectors (PSDs), called H3DD-UM, is presented. The ASIC integrates 128 channels for anode events and two channels for cathode events. Each channel provides low-noise charge amplification with an adjustable dynamic range to cover up to 10 MeV, followed by two programmable antialiasing filters with different gains, each feeding a 256-cell waveform-sampling circuit. The sampling architecture makes use of a single rail-to-rail amplifier configured to cancel offset errors and achieve high sampling uniformity. A dedicated circuit in the channel provides analog shaping for low-noise discrimination of the events. The number of stored samples before and after discrimination is fully programmable. The ASIC integrates numerous functions, including pixel leakage current measurement, analog monitoring, test pulse generators, temperature sensor, and interchip communication for use in systems with multiple modules.