PACIFIC: The readout ASIC for the SciFi Tracker of the LHCb detector

Abstract

PACIFIC is a 64 channel mixed-signal ASIC designed for the scintillating fiber tracker readoutand developed for the LHCb upgrade in 2019/20. It connects without any extra components tothe 128 channel double-die SiPM arrays sensing the fibres output signal. The analog processingchain begins with a current conveyor followed by a tunable fast shaper and a gated integrator.The signal is digitized with three configurable discriminators at 40MHz. The results of everyfour channels are encoded to two bits per channel, serialized and transmitted at 320MSa/s over adifferential SLVS data link. PACIFIC has been designed using a 130nm CMOS technology andpower consumption kept below 10mW/channel.