600 V N-channel MOSFET in a SOT-223 — what it is and where it fits
The Infineon BSP125L6433 is a SIPMOS N-channel enhancement-mode power MOSFET rated for 600 V drain-source breakdown and 120 mA continuous drain current. It comes in a surface-mount SOT-223 package (PG-SOT223-4-21) and operates across a -55 to 150 °C junction temperature range. This is a small-signal high-voltage switch — think auxiliary supplies, bias rails, relay pre-drivers, and off-line start-up circuits where the load is under 120 mA and the bus voltage can hit 600 V. The 45 Ohm on-resistance at 10 V gate drive is high by power-conversion standards, but that is the trade-off for the 600 V blocking capability in a small footprint.
Lifecycle and compliance
This part carries an Active lifecycle status and is ROHS3 compliant. No end-of-life notice or last-time-buy window is in effect. For a BOM freeze or a new-design qualification, the BSP125L6433 is a current-production part with no forced redesign horizon. The SIPMOS series is Infineon's established high-voltage MOSFET family; the part is widely stocked through both franchised and independent channels.
