The ATLAS LAr calibration board

In order to calibrate the ATLAS Liquid Argon calorimeters to an accuracy better than 1%, over 16 bits dynamic range, 2 prototype boards with 128 pulse generators have been built using DMILL components. The logic of control is able to enable the required channels, to load the DAC value, to delay and send the calibration command. The DAC voltage is distributed to the 128 channels in order to produce the 2 μA – 200 mA precision current. The voltage to current conversion uses a low-offset opamp and a 0.1% 5Ω resistor. Exhaustive measurements have been performed on this prototype (uniformity, linearity, jitters ...) and will be presented in detail.