It is a current-production Infineon HITFET device, not an NRND or EOL part that forces a redesign cycle.
70 mOhm Rds(on) — the conduction loss floor
The typical on-resistance is 70 mOhm. At the 2.17 A maximum continuous output, that works out to about 330 mW of conduction loss at 25°C junction. The PG-SOT223-4 package with its exposed tab can handle that without thermal runaway, but derate above 85°C ambient — the RthJA climbs and the 150°C junction limit comes into play.
42 V load rail — 24 V automotive with headroom
The load voltage is rated to 42 V maximum. That covers a 24 V nominal industrial bus with margin for transients, and it handles the 12 V automotive load-dump spike that can hit 35 V. The 2.17 A output ceiling suits solenoid, relay, lamp and small motor loads in those environments.
Built-in fault protection — no external clamp needed
The BTS3118NHUMA1 integrates current limiting (fixed), over-temperature shutdown, and over-voltage protection. That means you can drop this switch into a 24 V or 12 V load circuit without adding a series resistor for inrush or a TVS for inductive kickback — the device handles it internally. The non-inverting input and 1:1 ratio make it a straight drop-in for a logic-level gate signal.
PG-SOT223-4 footprint — board layout note
The package is PG-SOT223-4 (TO-261-4 equivalent). The exposed tab on the bottom is the drain connection and the primary thermal path. On a 2-layer board, a copper pour under the tab with vias to the ground plane keeps the junction temperature below 125°C at full load. The surface-mount assembly is standard reflow — no special profile needed.