FANSIC: a Fast ANalog SiPM Integrated Circuit for the readout of large silicon photomultipliers

Silicon photo-multipliers (SiPM) have been replacing traditional photomultiplier tubes in most light sensing applications. However, when large detection surface coverage is needed, photomultipliers (PMTs) are still the preferred choice. The main reasons are the sensor thermal noise and the duration of the fast component of its signal, both increasing with the sensor surface. In this work we propose an application specific integrated circuit (ASIC), called Fast ANalog SiPM Integrated Circuit (FANSIC), for the readout of large SiPMs addressing these limitations. The ASIC has an active summation stage, which allows to divide a large detection surface into smaller ones offering faster response both in single ended and differential outputs. The high input bandwidth allows to reach full-width-half-maximum (FWHM) signals or the order of 3--5 ns which limits the impact of internal and external uncorrelated noise. The results of the first implementation of FANSIC, designed in CMOS 65 nm technology, is described in this paper.