650 V N-channel for offline flyback and PFC stages
The STD9N65M2: This N-channel MOSFET is rated for 650 V drain-source and 5 A continuous drain current.
Gate charge and switching behaviour
A 5 V gate signal leaves the channel partially enhanced and the on-resistance significantly higher than the datasheet maximum.
DPAK thermal and footprint considerations
The TO-252 (DPAK) package with exposed drain tab requires a copper landing pad on the PCB — the tab is the primary heat path. Surface-mount assembly with standard reflow profile; the tab solder joint carries no current but must be void-free for thermal transfer.