500 V, 4.5 A switch — where it lands in the power stage
The IRF430 is an N-channel enhancement-mode MOSFET from the HEXFET® series, rated for 500 V drain-source breakdown and 4.5 A continuous drain current. The 1.8 Ohm maximum on-resistance at Vgs = 10 V sets the conduction loss floor for a given load current — at 4.5 A the resistive loss is about 36 W, so the 75 W package power limit (TO-220AB through-hole) leaves thermal headroom only with adequate heatsinking.
Total gate charge is 40 nC at Vgs = 10 V — a 1 A gate driver charges the gate in about 40 ns, which is fast enough for hard-switched converters in the 50–100 kHz range.
The TO-220AB through-hole package is a standard power footprint with a metal tab for heatsink mounting — the drain tab is at drain potential, so an insulating pad or thermal compound is required for a grounded heatsink.