P-channel power switch for high-side load control
The Infineon IPD70P04P4L08ATMA2 is a P-channel enhancement-mode MOSFET from the OptiMOS®-P2 series, built for high-side switching where a positive supply rail is controlled without a charge-pump or bootstrap driver. With a 40 V drain-source breakdown and 70 A continuous drain rating at 25 °C case temperature, it handles 12 V and 24 V automotive loads, battery-origami circuits, and reverse-polarity protection with comfortable margin.
7.8 mOhm Rds(on) — what it buys the power budget
At lower currents typical of a 30 A load, the I²R loss drops to roughly 7 W, which a standard 2-oz copper pour on a two-layer board can handle with the right via stitching to the backplane. The 92 nC total gate charge at 10 V sets the drive requirement: a gate driver sourcing 1 A can switch the FET in about 92 ns, but the input capacitance of 5430 pF at 25 V means the driver must deliver a peak current well above the average to avoid Miller-plateau slowdown during hard-switching transitions.
Package and rework — the DPak reality
The TO-252-3 (DPak) package with a single drain tab is one of the more forgiving surface-mount power packages under a hot-air station. The exposed tab is the drain connection and the primary heat path; a good solder joint under the tab is critical for both electrical and thermal performance. The two source pins and the gate pin are on the same side, so orientation is clear from the chamfer on the plastic body. Will it survive the hot air? Yes — if the board copper pour under the tab isn't a massive ground plane that sucks heat away faster than the preheat can keep up. A 150 °C preheat on the bottom side and a focused 350 °C nozzle on the tab for 20 seconds lifts it clean without lifting the pad.
Temperature grade and deployment envelope
The 175 °C ceiling is the absolute maximum junction temperature — the designer should derate the continuous current per the datasheet's thermal impedance curve for the actual board layout and ambient conditions.