The purpose of this study is to characterize the single-event-effects (SEE) performance due to heavy ion irradiation of the TMUX582F-SEP, latch-up immune 8:1 multiplexer with adjustable fault thresholds. Heavy-ions with an LET_EFF of 43MeV-cm²/mg were used to irradiate six production devices. Flux of ~10⁵ ions / cm² *s and fluence of ~10⁷ ions / cm² per run were used for the single-event latch-up (SEL) characterization and flux of ~10⁴ ions / cm² *s and fluence of ~10⁶ ions / cm² per run were used for the single-event transients (SET) characterization. The results demonstrate that the TMUX582F-SEP is SEL-free up to LET_EFF = 43MeV-cm²/ mg at 125°C. Additionally, the single-event transient (SET) performance for output voltage excursions ≥ |10%| from the nominal voltage are discussed.