During SEL characterization, the device was heated using forced hot air, maintaining the DUT temperature at 125°C. The die temperature was monitored during testing using a T-Type thermocouple attached to the thermal pad vias (on the bottom side of the EVM) with thermal paste. The thermocouple was held in-place by using high temperature tape (kapton-tape). Die-to-thermocouple temperature was verified using a IR-camera.

The species used for the SEL testing was a Krypton (⁸⁴Kr) ion with an angle-of-incidence of 44.38°, degraded by 3-steps of a degrader angle of 47.75° for an LET_EFF = 43 MeV·cm²/mg (for more details refer to Section 6). The kinetic energy in the vacuum for this ion is 2.081 GeV (25-MeV/amu line). Flux of approximately 10⁵ ions/cm²·s and a fluence of approximately 10⁷ ions/cm² were used for the four runs. Run duration to achieve this fluence was approximately 2 minutes. The two devices were powered up and exposed to the heavy-ions using the maximum recommended voltage of 32 V and maximum load of 6 A. No SEL events were observed during all four runs, indicating that the TPS7H4010-SEP is SEL-free. Table 9-3 shows the SEL test conditions and results. Figure 8-1 shows a plot of the current vs time for run # 1.

Using the MFTF method described in Single-Event Effects (SEE) Confidence Interval Calculations application report and combining (or summing) the fluences of the four runs @ 125°C (3.99 × 10⁷), the upper-bound cross-section (using a 95% confidence level) is calculated as:

σ_SEL ≤ 9.23 × 10^–8 cm²/device for LET_EFF = 43 MeV·cm²/mg and T = 125°C.