The ETROC Project: Precision Timing ASIC Development for CMS MTD Endcap Timing Layer (ETL) upgrade

The MIP Timing Detector (MTD) of the Compact Muon Solenoid (CMS) will provide precision timing measurements with time resolution down to 30 ps level for every charged particle up to a pseudo-rapidity of |η|=3. This upgrade will mitigate the impact of pile-up interactions expected under the High-Luminosity LHC (HL-LHC) running conditions. The endcap region of the MTD, named the Endcap Timing Layer (ETL), will be comprised of a two-disk system of MIP-sensitive silicon low-gain avalanche diodes (LGADs), covering the high-radiation pseudo-rapidity region 1.6 < |η| < 3.0. The LGADs will be read out with the Endcap Timing Readout Chip (ETROC), which is designed to handle a 16×16 pixel cell matrix, each pixel cell being 1.3×1.3 mm^2 to match the LGAD sensor pixel size. We present recent progress in the design of ETROC and prototype testing results.