Study of DMILL TTCrx ASICs properties.

The TTCrx ASIC sends 40.08 MHz LHC clock and trigger L1 Accept signals to the electronics subsystems in the ATLAS experiment. This note reports studies on jitter variation versus programmable delay and phase delay versus temperature of the deskew clocks. The ATLAS experiment requires that the total TTCrx clock jitter relative to the LHC clock must be less than 100 ps RMS, and the maximum found on testbench is roughly 70 ps. The temperature evolution of the TTCrx delays has been evaluated and was found to be about 34 ps/°C. Finally, the jitter effects on energy and time reconstruction have been studied within the LArg electronics system, using the EM Barrel Calorimeter reconstruction method. The amplitude relative uncertainty is between 10.E-5 and 10.E-4, and is not negligible only at high energies. The time uncertainty is, at worst, of the same magnitude as the jitter introduced in simulation (about 50 ps).