400 V N-channel in a SOT-223 — what it fits
The Infineon BSP324H6327XTSA1 is a 400 V N-channel SIPMOS MOSFET in a PG-SOT223-4 surface-mount package. The 400 V drain-source voltage suits offline auxiliary supplies, flyback clamp circuits, and high-voltage DC-DC converters where the current is modest.
On-resistance and gate drive — the thermal trade-off
With 25 Ohm Rds(on) at 10 V gate drive, conduction loss at 170 mA is about 0.72 W — the 1.8 W package dissipation limit (Ta) leaves some headroom, but the junction will run hot in still air. The 5.9 nC gate charge (Qg at 10 V) keeps switching losses low enough for low-frequency flyback converters up to a few tens of kilohertz. The gate threshold voltage is 2.3 V max at 94 µA drain current, so a 3.3 V logic-level gate drive will turn it on, but the Rds(on) is specified at 4.5 V and 10 V drive — expect higher on-resistance if driven below 4.5 V.
Temperature range and operating environment
Rated for junction temperature from -55°C to 150°C, this MOSFET can handle engine-bay ambient in automotive auxiliary loads or outdoor telecom power supplies where the board sees wide thermal cycling. The 150°C TJ max is the absolute limit; derate power dissipation above 25°C ambient per the datasheet curve.
Sourcing and lifecycle
ROHS3 compliant.