30 V N-channel in an SO-8 — what the 8.5 mOhm Rds(on) buys you
The IRF8721TRPBF is an Infineon HEXFET N-channel MOSFET rated for 30 V drain-source and 14 A continuous drain at 25 °C case temperature. The 8.5 mOhm max on-resistance at Vgs = 10 V sets the conduction loss at about 1.7 W at 14 A — well within the 2.5 W package limit at 25 °C ambient, but the SO-8 footprint means the PCB copper area is the real heatsink. For a 5 A load the dissipation drops to 0.21 W, so the part runs cool on a standard two-layer board.
Gate drive at 4.5 V — one less driver on the BOM
Gate charge is specified at 12 nC max with Vgs = 4.5 V, which means a 5 V logic rail can drive the gate directly through a series resistor. No separate gate-driver IC needed for switching frequencies up to a few hundred kHz — the 1040 pF input capacitance at 15 V drain gives a rough switching-loss estimate for the dead-time budget in a synchronous buck.
The 150 °C max junction means the 2.5 W package limit must be derated above 25 °C; a 1 W dissipation at 85 °C ambient leaves about 65 °C headroom to the junction limit with a reasonable copper pour.