STiC - A mixed mode chip for SiPM ToF applications

STiC is a mixed mode 16-channel ASIC chip in UMC 0.18 /Lm CMOS technology aiming at Silicon Photomultiplier (SiPM) readout with optimal timing resolution. It is designed for ToF measurements in HEP and medical imaging applications and dedicated in particular to the ENDOToFPET·US project, which aims at providing a powerful endoscopic Time· of-Flight PET system for early prostate and pancreas cancer diagnostics. The goal of this endoscopic system is to provide a spatial resolution of the order of 1 mm and a Time-of-Flight resolution of 200 ps FWHM. The STiC chip has a differential structure. However, SiPMs can be connected either differentially or single-endedly. The timing and charge information of the input signal - both required for a high-resolution ToFPET system - are encrypted into two time stamps and processed later by an embedded TDC module with a timing resolution of better than 20 ps. The digitized data are stored first on an on-chip SRAM block and then transferred via a 160 MBit LVDS serial link using 8/10-bit encoding. The simulated single pixel timing jitter is less than 15 ps for Hamamatsu SI0362-11-50 MPPCs. A special linearization method has been used to obtain a linear charge response in a very wide range. The total power consumption is about 20 m W per channel. Design details as well as first measurement results will be presented.