During the SEL testing the device was heated to 125°C by using PID controlled heat gun (MISTRAL 6 System (120V, 2400W)). The temperature of the die was constantly monitored during testing at TAMU through an IR camera integrated into the control loop to create closed-loop temperature control. The die temperature was verified using a standalone FLIR thermal camera prior to exposure to heavy ions at KSEE.

The species used for the SEL testing was ¹⁰⁹Ag (TAMU) at 15MeV/nucleon and ¹⁰⁹Ag (KSEE) at 19.5MeV/nucleon. For both ions an angle of incidence of 0° was used to achieve a LET_EFF of ≈ 48MeV·cm²/mg (for more details refer to Table 8-4). The kinetic energy in the vacuum for ¹⁰⁹Ag (TAMU) is 1.635 GeV and ¹⁰⁹Ag (KSEE) is 2.125GeV. Flux of ≈9.14 × 10⁴ to 1.26 × 10⁵ ions/(cm²×s) and a fluence of ≈10⁷ ions/cm² per run was used. Run duration to achieve this fluence was ≈ 2 minutes. The 6 devices were powered up and exposed to the heavy-ions using the maximum recommended input voltage of 14V and max programmable V_LDO voltage of 5.5V. Depending on the operational mode PVIN was either tied to VIN or VLDO, for more information refer to the Table 6-1. No SEL events were observed during all six runs, indicating that the TPS7H5020-SEP is SEL-free up to 48 MeV·cm²/mg.Table 8-4 shows the SEL test conditions and results. Figure 7-1 and Figure 7-1 show a plot of the current versus time for runs #1 and #3, respectively.

Using the MFTF method described in Single-Event Effects (SEE) Confidence Interval Calculations application report and combining (or summing) the fluences of the six runs at 125°C (6 × 10⁷), the upper-bound cross-section (using a 95% confidece level) is calculated as:

σ_SEL ≤ 6.15x 10^-8 cm²/device for LET_EFF = 48 MeV·cm²/mg and T = 125°C.