The TOFHIR2 readout ASIC of the CMS MTD Barrel Timing Layer

The CMS Detector will be upgraded for the HL-LHC to include a MIP Timing Detector (MTD). The MTD will consist of barrel and endcap timing layers, BTL and ETL, respectively, providing precision timing of charged particles. The BTL sensors are based on LYSO:Ce scintillating crystals coupled to SiPMs with TOFHIR2 ASICs for the front-end readout. A resolution of 30-40 ps for MIP signals at a rate of 2.5 Mhit/s per channel is expected at the beginning of HL-LHC operation. We present an overview of the TOFHIR2 requirements and design, simulation results, and the first measurements with silicon samples.