100 V, 6 mOhm — the conduction loss number
The AUIRFS4310ZTRL is an Infineon N-channel HEXFET power MOSFET rated for 100 V drain-source and 120 A continuous drain current.
Total gate charge is 170 nC at 10 V.
175 °C junction — where it goes
That 175 °C ceiling is the threshold for under-hood automotive or industrial environments where ambient air hits 105 °C and the self-heating from 120 A pulses pushes the die temperature past what a 150 °C-rated part could survive.
Listed as Active by Infineon — no end-of-life notice or last-time-buy clock is running. RoHS compliance is standard for the AUIRFS4310ZTRL suffix.