The STD25NF10LT4 is an STMicroelectronics STripFET™ II N-channel power MOSFET rated at 100 V drain-source and 25 A continuous drain current at a 25 °C case temperature. The 35 mOhm maximum on-resistance at a 10 V gate drive sets the conduction loss floor for a 12.5 A load — at that point the dissipation is about 5.5 W, which the DPAK package can sink to a copper pour on a 1 oz board with reasonable airflow.
Maximum gate charge is 52 nC at a 5 V drive. For a 100 kHz hard-switching converter, that translates to about 5.2 mA average gate-drive current — well within a standard totem-pole driver. At 4.5 V the on-resistance rises above the 35 mOhm maximum — the design should budget for the higher conduction loss if the gate rail is 5 V logic-level rather than a dedicated 10 V supply.
DPAK footprint and thermal management
The TO-252-3 (DPAK) package has an exposed tab on the drain. A 2 oz copper pour of at least 6 cm² is typical for keeping the junction below 125 °C at 15 A continuous.