During SEL characterization, the device was heated using forced hot air, maintaining device temperature at 125°C. A FLIR (FLIR ONE Pro LT) thermal camera was used to validate die temperature to make sure the device was accurately heated (see Figure 4-2.) The species used for SEL testing was a Xenon (¹²⁹Xe) ion at 25MeV / µ with an angle-of-incidence of 0° for an LET_EFF of 50MeV-cm²/ mg. A fluence of approximately 1 × 10⁷ ions / cm² was used for each run.

The three devices were powered up and exposed to the heavy-ions using the maximum recommended supply voltage of 3.6V using a National Instruments™ PXI Chassis PXIe-4139 on VCC and input 1A and a 3.6V, 10MHz square wave on input 4A using a National Instruments™ PXI Chassis PXIe-5423 function generator. The run duration to achieve this fluence was approximately 100 seconds. As listed in Table 5-2, no SEL events were observed during the eight runs, indicating that the SN55LVTA4-SEP is SEL-free. Figure 5-1, Figure 5-2, and Figure 5-3 show the plots of current versus time for runs one, three, and six, respectively.

A single unit was tested with a fluence of 1.5E+07 using the same bias condition as above. No SEL events occurred on these runs either.

Figure 5-1 Current Versus Time for Run 1 of the SN55LVTA4-SEP at T = 125°C

Figure 5-2 Current Versus Time for Run 3 of the SN55LVTA4-SEP at T = 125°C

Figure 5-3 Current Versus Time for Run 6 of the SN55LVTA4-SEP at T = 125°C

No SEL events were observed, indicating that the SN55LVTA4-SEP is SEL-immune at LET_EFF = 50MeV-cm² / mg and T = 125°C. Using the MFTF method shown in Single-Event Effects (SEE) Confidence Internal Calculations , the upper-bound cross-section (using a 95% confidence level) is calculated as: