What the 800 V rating means for your offline supply
The 800 V drain-source breakdown voltage gives you 200 V of headroom above a 600 V rail — enough to absorb the reflected voltage spike in a universal-input flyback without an external snubber eating into efficiency. Gate charge is 9 nC typical at 10 V, which keeps the gate-drive loss low even at switching frequencies above 100 kHz. The 175 pF input capacitance at 500 V drain-source means the driver sees a light capacitive load — a small-signal MOSFET driver or a PWM controller totem-pole can drive it directly.
Package and temperature — fits a reflow line and a hot environment
The PG-TO252-3 (DPak) surface-mount package has a standard footprint with the tab as the drain connection.