Total dose radiation effect simulations on a high-precision data acquisition system

A novel method to evaluate total dose radiation response on large mixed signal circuits is described. The method is based on partly behavioral, partly structural simulation on the VHDL-AMS language. Results obtained with the developed simulation method are compared to total dose testing results of an embedded high-precision data acquisition system. The system was total dose tested until functional failure in a Cobalt-60 irradiation chamber. Photoemission microscopy (PEM) analysis showed severe TID induced leakage currents inside the 1.2 kbyte SRAM memory sub-system. The SRAM sub-system was TID simulated with the developed method, and the results were compared to the irradiation test results. The simulation results suggest that the drain-to-source leakage currents inside the SRAM sub-system might not be the only cause for the system failure.