The upgraded front-end electronics of the CMS electromagnetic calorimeter for the HL-LHC

The Compact Muon Solenoid detector was originally designed to operate for about ten years, for LHC instantaneous luminosity up to 1$\cdot$10$^{34}$ cm$^{-2}$ s$^{-1}$ and integrated luminosity of 500 fb$^{-1}$. The High Luminosity LHC will increase the instantaneous luminosity by about a factor of 5 from current levels and CMS will accumulate an integrated luminosity of 3000 fb$^{-1}$ by about 2035.With such high luminosity the electromagnetic calorimeter of CMS will have to cope with a challenging increase in number of interactions per bunch crossing and in radiation levels.The front-end readout electronics will be completely redesigned, with the goals of providing precision timing, low noise, sampling rate 4 times higher than the current one and added flexibility in the trigger system.