During SEL characterization, the device was heated using forced hot air, maintaining IC temperature at 125°C. A FLIR (FLIR ONE Pro LT) thermal camera was used to validate die temperature to make sure that the device was accurately heated (see Figure 3-5). The species used for SEL testing was a Xenon (¹²⁹Xe) ion at a linac energy of 25 MeV / µ with an angle-of-incidence of 0° for an LET_EFF of 43 MeV-cm² / mg. A fluence of approximately 1 × 10⁷ ions/cm² were used for the runs.

The three devices were powered up and exposed to the heavy-ions using the maximum recommended supply voltage of 5.5-V using a National Instruments PXI Chassis PXIe-1085. The run duration to achieve this fluence was approximately 2 minutes. As listed in Table 5-1, no SEL events were observed during the nine runs, indicating that the SN54SC4T125-SEP is SEL-free. Figure 5-1, Figure 5-2, and Figure 5-3 show the plot of current versus time for run numbers one, four, and seven, respectively.

Figure 5-1 Current versus Time for Run Number 1 of the SN54SC4T125-SEP at T = 125°C

Figure 5-2 Current versus Time for Run Number 4 of the SN54SC4T125-SEP at T = 125°C

Figure 5-3 Current versus Time for Run 7 of the SN54SC4T125-SEP at T = 125°C

No SEL events were observed, indicating that the SN54SC4T125-SEP is SEL-immune at LET_EFF = 43 MeV-cm² / mg and T = 125°C. Using the MFTF method shown in Single-Event Effects (SEE) Confidence Interval Calculations, the upper-bound cross-section (using a 95% confidence level) is calculated as: