Experimental Estimation of the Window of Vulnerability for Logic Circuits

Accurate estimation of single event upset rates for complex combinational logic circuits is extremely challenging due to the difficulties involved in calculation of different masking factors. This paper introduces the concept of an effective value of the window of vulnerability which is calculated experimentally for 28 nm bulk CMOS combinational logic circuits. Results suggest that the window of vulnerability for different input conditions of the same circuit are similar but that of different circuits could differ. The difference in gate type and topology is identified as the key reason for the differences in window of vulnerability. The window of vulnerability due to alpha particle irradiation for different circuits is between 30-60 ps which compares reasonably with SET pulse-width distributions reported in the past. The effective value of the window of vulnerability could be used to simplify logic error rate calculations.