400 V, 9 A — where this MOSFET fits the BOM
The STP11NK40Z: This part is aimed at offline switch-mode power supplies, AC-DC converters, and lighting ballasts where the 400 V blocking voltage provides adequate derating for 240 VAC rectified rails.
The 4.5 V maximum gate threshold at 100 µA drain current means a 10 V gate drive is needed to guarantee the on-resistance spec; at 5 V drive the Rds(on) will be significantly higher, so logic-level gate signals won't cut it. The SuperMESH™ technology includes avalanche energy rating, though the ledger does not specify the single-pulse or repetitive limit — treat the 110 W dissipation as the thermal ceiling for steady-state operation.