That 1700 V rating puts it squarely in the high-voltage offline conversion space — think flyback and forward converters in industrial power supplies, auxiliary supplies for three-phase motor drives, and solar microinverter stages where the DC bus sits at 600–1000 V and you need margin for switching transients. The 13 Ohm maximum Rds(on) at 10 V gate drive is the number to budget for conduction loss; at 1.3 A test current the drop is about 17 V, so this is a device sized for a few hundred milliamps of real load when you factor in the 63 W dissipation ceiling and the junction temperature derating.
Gate drive and threshold — not a logic-level part
The maximum gate-source voltage is ±30 V, which gives some headroom for ringing on a long gate trace, but you still want a gate resistor and a zener clamp if the drive transformer or bootstrap supply can overshoot. Gate charge is 44 nC at 10 V, so the driver needs to source and sink that charge fast enough to keep switching losses under control at the target frequency.
Package and thermal — TO-3PF full-pack
The STFW3N170 comes in a TO-3P-3 Full Pack (TO-3PF) through-hole package. The junction temperature range is -55 to 150 °C, covering industrial and some automotive under-hood environments. Input capacitance is 1100 pF at 100 V drain-source, which is modest and keeps the drive power reasonable.