Development of ATLAS Liquid Argon Calorimeter Readout Electronics for the HL-LHC

The LHC high-luminosity upgrade in 2024-2026 requires the associated detectors to operate at luminosities about 5-7 times larger than assumed in their original design. The pile- up is expected to increase to up to 200 events per proton bunch-crossing. To be able to retain interesting physics events at electroweak energy scales, increased trigger rates are foreseen for the ATLAS detector. At the hardware selection stage acceptance rates of up to 1 MHz are planned, combined with longer latencies up to 40 micro-seconds in order to read out the necessary data from all detector channels. The current readout of the ATLAS Liquid Argon (LAr) Calorimeters does not provide sufficient buffering and bandwidth capabilities. For these reasons a replacement of the LAr front-end and off-detector readout systems is foreseen for all 182,500 readout channels, with the exception of the cold pre-amplifier and summing devices of the hadronic LAr Calorimeter. The new low-power electronics must be able to capture the triangular detector pulses of about 400- 600 nano-seconds length with signal currents up to 10 mA and a dynamic range of 16 bits. Results from performance simulation of the calorimeter readout system for different options and results from first tests of the components are presented.