The ATLAS Liquid Argon Calorimeter readout electronics will be upgraded to withstand higher radiation doses and harsher conditions during the HL-LHC. In this context, the upgraded readout chain will include front-end, calibration, processing, and timing control boards. The front-end boards will amplify and digitize the ionization signal with high precision and low noise. Custom made chips for amplifying, shaping and digitize the calorimeter signals have been developed, demonstrating stability under irradiation tests. Calibration boards will ensure precise calibration across all channels by using custom ASICs which will be also stable under irradiation. The digitized signal will be processed for energy estimation and time stamping purposes b...