100 V N-channel MOSFET in SOT-223 — where it fits
The BSP373NH6327XTSA1: Surface-mount PG-SOT223-4 package, same footprint as standard SOT-223.
Rds(on) and gate drive — sizing the gate circuit
At 1.8 A the conduction loss is I²R = 0.78 W, which consumes nearly half the 1.8 W package dissipation before any switching losses are added. The gate charge of 9.3 nC at 10 V is low enough that a microcontroller GPIO with a series resistor can drive the gate at moderate frequencies (a few tens of kHz); above 100 kHz a dedicated gate driver is advisable to keep switching edges clean.