Gate drive and switching speed
The IRF640NPBF: Total gate charge is 67 nC at 10 V — the driver must supply this charge per switching cycle. At 100 kHz the average gate-drive current is Qg × f = 6.7 mA, well within a standard gate-driver IC's capability, but the peak current from the driver's output stage must still charge the gate capacitance quickly enough to avoid the Miller plateau dwell. The 4 V typical gate threshold at 250 µA drain current means a 10 V drive rail provides about 6 V of overdrive, keeping Rds(on) at its rated minimum.
Package and thermal interface
Through-hole TO-220AB package (TO-220-3) — the tab is the drain. For a PCB layout, the tab is soldered to a copper island on the board or clamped to a heatsink; the junction-to-case thermal resistance is low enough that the 150 W limit is real only with a proper thermal path. Operating junction temperature spans -55 to 175 °C — this is the full industrial temperature range with margin for self-heating under continuous load. The 175 °C ceiling means the device can handle transient overloads that push junction temperature above 150 °C without immediate failure, though long-term reliability degrades above 125 °C.