Each cell of the Tile Calorimeter is read-out by two PMTs in order to provide redundancy in the light read-out and improve spatial uniformity. The total number of channels is approximately 10310. The breakdown is given below:
The energy deposited in a single cell can vary from 350 MeV for muons up to 1.5 TeV for several events per year. This implies a 16 bit dynamic range for the energy measurement. The design of the electronics is mainly constrained by the avaible space, residual magnetic fields from the solenoid and the toroid, and irradiation.