The Selection of a radiation-tolerant DAC for the LHC (Part II: CMOS technology)

Total dose & neutron tests on commercial CMOS digital-to-analog converters have been carried out. These results are related to those ones presented in the previous paper. This kind of devices is much more sensitive to ionizing radiation than to neutrons. That radiation changes the value of the MOSFET threshold voltage and this can put digital circuits out of action. In this case, the gradual destruction of the digital inputs was observed as a diminution of the output voltage levels. Also, the gamma radiation generates leakage currents that increase the consumption. Due to these converters tolerated less total radiation dose, their use in the LHC has been refused and the fast bipolar technology converters will be employed