The purpose of this study is to characterize the single-event-effects (SEE) performance due to heavy-ion irradiation of the THVD9491-SEP, 1.2V to 5.5V octal bus transceiver. Heavy-ions with an LET_EFF of 47.5MeV × cm² / mg were used to irradiate six production devices. Flux of approximately 10⁵ions/cm² × s and fluence of approximately 10⁷ions / cm² per run were used for the single-event latch-up (SEL) characterization and flux of approximately 10⁴ions / cm²× s and fluence of approximately 10⁶ions / cm² per run were used for the single-event transients (SET) characterization. The results demonstrate that the THVD9491-SEP is SEL-free up to LET_EFF = 47.5MeV × cm²/ mg at 125°C. Additionally, the single-event transient (SET) performance for output voltage excursions ≥ |10%| from the nominal voltage are discussed.