Future of the ATLAS Liquid Argon Calorimeter

Improvements to the ATLAS liquid argon calorimeter (LAr) as part of the Phase-I upgrades (2019-2020) are currently underway. A new baseplane will be installed to split the calorimeter signal between the new LAr Trigger Digitizer Boards and legacy Tower Builder Boards. Further improvements for the Phase-II upgrades (2024-2026) are planned in preparation for the High-Luminosity LHC (HL-LHC). The HL-LHC will operate at luminosities 5-7 times the LHC's original design. New readout electronics are necessary to cope with the increased radiation damage and for compatibility with the new trigger system. The 182,500 LAr calorimeter cells will be readout at 40 MHz with a 16 bit dynamic range. For the first time, full LAr calorimeter granularity will be sent to the lowest level trigger processors. Prototypes of the new front-end electronics have been tested, and design studies of the off-detectors digital filtering algorithms and bandwidth requirements performed. An overview of the Phase-II LAr readout electronic design is presented.