900 V CoolMOS — the 400 V bus workhorse
The Infineon IPW90R120C3XKSA1 is a 900 V N-channel CoolMOS power MOSFET in a TO-247-3 through-hole package. It's the part you reach for when a 600 V device leaves no headroom on a 400 V DC bus with switching transients — the 900 V Vdss rating gives you 2.25× derating on a nominal 400 V rail, which covers the ringing from a hard-switching half-bridge without avalanche stress.
120 mOhm Rds(on) — conduction loss and heatsink budget
The 417 W power dissipation rating (Tc) tells you the package can sink that heat if the case temperature is held down, but in a real 26 A continuous load you are looking at a substantial extruded heatsink or forced air.
Gate charge and drive current
270 nC total gate charge at 10 V means the gate driver must source and sink that charge each switching cycle. The 6800 pF input capacitance at 100 V drain-source confirms the gate looks like a large capacitive load.
Temperature range and environment
The TO-247-3 through-hole package (PG-TO247-3-21) allows manual rework and high-reliability solder joints in high-vibration environments.
Lifecycle and compliance
ROHS3 compliant, so it clears the EU RoHS directive without an exemption. The CoolMOS series is a mature Infineon platform with a long production history; no official successor has been announced for this voltage/current tier.