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. A 100 kHz switching frequency demands 17 mA average from the gate driver just to charge and discharge the gate — the driver must be sized for peak current well above that to avoid miller-plateau slowdown. The ±20 V maximum gate-source rating gives headroom for driving the gate above the 10 V test point to further reduce on-resistance in high-current pulses.
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. The D2PAK (TO-263) surface-mount package with an exposed drain tab needs a copper pour on the PCB to pull heat out — the thermal resistance to ambient depends on the board area, not just the package.
Lifecycle and compliance
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.