The IRF7451TRPBF is a 150 V, 3.6 A N-channel HEXFET® MOSFET in an 8-SOIC (0.154-inch body width) surface-mount package. It is designed for medium-voltage DC-DC converters, secondary-side synchronous rectification, and load switches in 48 V and 72 V bus systems where the drain-source voltage ceiling needs headroom above the nominal rail.
Conduction and switching — the numbers that set the thermal budget
At the full 3.6 A rating, I²R loss reaches about 1.17 W, which must fit inside the 2.5 W package power dissipation limit at 25°C ambient — derating above that temperature is required. Gate charge totals 41 nC at 10 V. For a 100 kHz switching frequency, the average gate-drive current needed is 4.1 mA — within the capability of most dedicated MOSFET drivers, but worth checking against the driver's peak source/sink rating if the gate resistor is low. Input capacitance is 990 pF at 25 V drain-source. This capacitance, together with the gate charge, determines the switching energy per cycle; the 990 pF figure is moderate for a 150 V part and keeps the Miller plateau duration manageable in hard-switched topologies.
Temperature range and package — what the 150°C junction buys you
The 150°C Tj(max) also provides derating headroom for designs targeting 105°C ambient with a 20% margin on junction temperature. The 8-SOIC package (supplier device package 8-SO) has a 0.154-inch body width and 0.050-inch lead pitch. The copper pad area on the PCB under the die attach region directly influences thermal resistance — a 1-inch² copper pour on a 2-ounce board can drop RthJA significantly below the free-air value.