400 V, 2 A N-channel — SuperMESH3 in a DPAK
At 2 A the conduction loss hits about 13.6 W — well within the 30 W package dissipation limit at the case, but the junction-to-ambient thermal path in a DPAK will need a decent copper area or a heatsink to keep the junction below 150 °C.
The STD3N40K3 carries an Obsolete lifecycle status. STMicroelectronics has ended production, and no last-time-buy window remains open through the factory channel.
DPAK footprint and temperature range
The DPAK (TO-252) package has a tab that is electrically the drain.