High-side switch for 24 V industrial loads — 2.8 A, 50 mOhm
The STMicroelectronics VN540-E is a single-channel high-side power switch from the VIPower™ family, designed to drive resistive, inductive, and lamp loads on a 10 V to 36 V supply rail. It delivers up to 2.8 A continuous output with a typical on-resistance of 50 mOhm, which keeps conduction losses manageable at full load — about 0.4 W dissipation at 2.8 A, well within the Pentawatt-5 package's thermal budget if the copper area under the tab is adequate. The switch is self-contained: it needs no external Vcc supply (the logic supply is derived from the load voltage), and its On/Off interface is non-inverting, so a logic high on the input turns the output on. Built-in fault protection includes fixed current limiting and over-temperature shutdown, which means the part can survive a shorted load or a stalled fan without immediate destruction — the thermal limit cycles the output until the fault clears.
Pentawatt-5 through-hole — rework-friendly, board-space trade-off
The VN540-E comes in a Pentawatt-5 package (vertical, bent and staggered leads), a through-hole format that is straightforward to hand-solder and rework — no hot-air station needed, and the staggered lead arrangement gives good mechanical retention on the board. The downside is board area: the package footprint is larger than an equivalent SMD part like a DPAK or SO-8, so it is better suited to plated-through-hole layouts where the tab can be soldered to a copper island for heat sinking. For applications that see sustained ambient above 70°C, the 2.8 A rating should be derated — the datasheet's thermal impedance curve is the guide.
Because the part is obsolete, any new design should avoid it unless the BOM is locked and the production run is short enough to cover from surplus stock. For a repair or a legacy-board refit, the VN540-E can still be sourced, but expect higher per-unit cost and longer lead times compared to an active-production part.