40V, 120A automotive MOSFET — what the 1.8 mOhm buys you
That sub-2 mOhm figure is what lets a designer size the heatsink smaller or push more current through the same TO-220 package.
Rework and mounting — TO-220 realities
The STP360N4F6 comes in a through-hole TO-220-3 package. That means it is hand-solderable and rework-friendly — you can pull it with a desoldering gun or hot air without lifting pads, unlike a surface-mount power package. But the thermal mass is high: the tab carries most of the heat, and the part is rated for 300 W dissipation at the case. Pin 1 orientation is standard for TO-220 — the tab is the drain, gate is the left pin when facing the part with the tab away from you. The through-hole mount also means the part sits above the board, so mechanical clearance and lead bending for vertical or horizontal mounting are design considerations.
Gate drive and switching — what the numbers tell you
The STP360N4F6 specifies a gate charge of 340 nC at 10 V and an input capacitance of 17930 pF at 25 V drain-source. These are not small numbers: the gate charge is high enough that a standard MCU GPIO cannot drive it directly — you need a gate driver capable of sourcing and sinking several amps for fast switching. The threshold voltage is 4.5 V max at 250 µA, which means the part is fully enhanced only above that level — another reason to budget a proper gate-drive rail.