During SEL characterization, the device was heated using a TDH35P10R0JE discrete power resistor soldered right under the thermal vias on the bottom layer of the board, maintaining the DUT temperature at 125°C. Prior to radiation, the die to thermocouple temperature was verified using a FLIR IR-camera.

The species used for the SEL testing was a silver (¹⁰⁹Ag) ion with an angle-of-incidence of 0° for an LET_EFF = 48 MeV × cm² / mg. For more details, see Section 5). The kinetic energy in the vacuum for this ion is 1.634 GeV (15-MeV /amu line). Flux of approximately 10⁵ ions / cm² × s and a fluence of approximately 10⁷ ions / cm² were used for the six runs. Run duration to achieve this fluence was approximately two minutes. The six devices were powered up and exposed to the heavy-ions using the maximum recommended voltage of 32 V and maximum load of 5.4 A (1.35 A per channel). The device was set up with OUT₁ operating in a single configuration and OUT₂, OUT₃, OUT₄ were operated in a parallel configuration. See Figure 6-1 for more details. OUT₁ was loaded to 1.35 A, while OUT₂, OUT₃, and OUT₄ were in parallel loaded to 4.05 A (1.35 A per channel). No SEL events were observed during all six runs, which indicates that the TPS7H2140-SEP is SEL-free. Table 8-3 lists the SEL test conditions and results. Figure 7-2 shows a typical plot of I_IN versus time for run 1.

Using the MFTF method shown in Single-Event Effects (SEE) Confidence Interval Calculations and combining (or summing) the fluences of the six runs at 125°C (5.78 × 10⁷), the upper-bound cross-section (using a 95% confidence level) is calculated as:

${\mathrm{\sigma }}_{\mathrm{S}\mathrm{E}\mathrm{L}}\mathrm{ }\le \mathrm{ }6.38\mathrm{ }\times \mathrm{ }{10}^{-8}\mathrm{ }{\mathrm{c}\mathrm{m}}^2\mathrm{ }/\mathrm{ }\mathrm{d}\mathrm{e}\mathrm{v}\mathrm{i}\mathrm{c}\mathrm{e}\mathrm{ }\mathrm{f}\mathrm{o}\mathrm{r}\mathrm{ }{\mathrm{L}\mathrm{E}\mathrm{T}}_{\mathrm{E}\mathrm{F}\mathrm{F}}\mathrm{ }=\mathrm{ }48\mathrm{ }\mathrm{M}\mathrm{e}\mathrm{V}\mathrm{ }\times \mathrm{ }{\mathrm{c}\mathrm{m}}^2/\mathrm{m}\mathrm{g}\mathrm{ }\mathrm{a}\mathrm{n}\mathrm{d}\mathrm{ }{\mathrm{T}}_{\mathrm{J}}\mathrm{ }=\mathrm{ }125°\mathrm{C}$ .