100 V, 9.7 A N-channel switch in TO-220
The IRF520NPBF: The TO-220-3 through-hole package keeps the part board-mountable with a single screw tab for heatsinking.
The gate threshold is specified at 4 V maximum with 250 µA drain current, but the Rds(on) is characterised at 10 V drive — this is not a logic-level FET.
Thermal and environmental reach
That 175°C ceiling suits environments where the heatsink is marginal or the ambient runs hot — motor drives in enclosures, engine-bay auxiliaries, or power supplies with constrained airflow. Maximum power dissipation is 48 W at the case, but derating above 25°C is aggressive; a real design budgets for the thermal resistance of the heatsink interface.