What this part is — a low-voltage, high-current N-channel switch
The Infineon AUIRF1404STRL is an N-channel enhancement-mode MOSFET from the HEXFET® series, built on planar stripe technology. It's rated for a 40V drain-source voltage and a continuous drain current of 75A at 25°C case temperature — a part sized for high-current switching in 12V and 24V automotive, industrial, and power-conversion rails. The 4mOhm maximum on-resistance at 95A and 10V gate drive keeps conduction losses low, while the 200nC gate charge at 10V tells you the gate-drive circuit needs to source a solid pulse to switch it fast.
40V Vdss — headroom for 12V/24V rails
A 40V drain-source breakdown gives comfortable derating margin on a 12V or 24V nominal bus. In a 24V system with transients, you've got roughly 16V of headroom before avalanche — enough for most automotive load-dump clamping scenarios. The 75A continuous current is a case-temperature rating; at higher ambient or with restricted heatsinking, derate per the thermal curve.
4mOhm Rds(on) — what it means for the BOM
At 95A and 10V gate drive, the maximum on-resistance is 4mOhm. That translates to roughly 36W conduction loss at full rated current — a number that drives heatsink selection and PCB copper area. The 200nC gate charge means the driver must supply about 2A peak for a 100ns switching transition; undersized gate-drive ICs will stretch the switching edges and increase crossover loss. Pair this part with a driver capable of at least 2A peak source/sink.
Temperature range and environment
Rated for junction temperatures from -55°C to 175°C, this MOSFET suits under-hood automotive, high-ambient industrial enclosures, and military-grade power stages. The D2PAK (TO-263) surface-mount package reflows onto a copper island on the PCB; that tab is the drain, so the PCB layout must account for high-current traces and thermal vias. The part will survive a hot-air rework cycle if you preheat the board — the tab's thermal mass is substantial, so a bottom-side preheater helps lift the part without lifting the pad.
Lifecycle and sourcing
The AUIRF1404STRL has an Active lifecycle status per the manufacturer.