SiC MOSFET Buying Guide: Infineon CoolSiC, Wolfspeed and ST for Buyers

By All Chip Supply · Published Oct 24, 2026

Silicon carbide (SiC) MOSFETs show up in EV chargers, solar inverters, industrial drives and high-efficiency power supplies. Buyers often receive quotes that look similar on voltage and RDS(on) but differ on package, gate-drive voltage and thermal limits. This guide explains what to lock before you order Infineon CoolSiC, Wolfspeed or ST parts, and how to write a cleaner RFQ.

What matters more than the headline RDS(on)

Marketing tables usually highlight blocking voltage and on-resistance at 25 °C. For a real design, also check:

• RDS(on) at your operating junction temperature, not only at 25 °C
• Package and pinout (TO-247-3, TO-247-4, surface-mount and module footprints are not interchangeable)
• Recommended gate-source voltage (SiC families differ; some need a negative off voltage)
• Safe operating area, short-circuit withstand and avalanche ratings
• Isolation and creepage for the module or package you chose
• Qualification (industrial vs automotive) encoded in the ordering code

A part that looks "cheaper per milliohm" can still be the wrong buy if the gate driver, snubber or heatsink on your board was designed for another family.

Infineon CoolSiC

Infineon's CoolSiC portfolio covers discrete MOSFETs and modules used in industrial and automotive power stages. Examples on our catalog include the Infineon CoolSiC IMZA120R020M1H and the IMW120R030M1H. For higher current stages, Infineon IGBT and hybrid modules such as the FF450R12ME4 still appear on many BOMs alongside SiC.

When you RFQ CoolSiC discretes, quote the full ordering code, package and packing. Related gate drivers and isolators are often sourced in the same BOM; see industrial semiconductors and power semiconductors.

Wolfspeed

Wolfspeed (formerly Cree's power business) is widely specified in 900 V and 1200 V SiC designs. Catalog examples include the C3M0065090D and the C3M0016120K. Check the recommended gate voltages in the datasheet carefully; they are not always the same as a silicon MOSFET habit from older designs.

Lead times and date-code availability on popular Wolfspeed codes can move quickly. If a second source is allowed, list only the codes your design team has already reviewed against the gate driver and layout.

ST and other silicon / controller parts in the same BOM

Many power boards mix SiC switches with silicon controllers and drivers. ST parts such as the L6599AD LLC controller often sit next to the power stage. Texas Instruments regulators and drivers, for example the TPS54331, also appear on the same RFQs. Quote those lines with the same packaging and date-code rules as the SiC switches so the kit arrives complete.

Browse power semiconductors for SiC MOSFETs, IGBT modules and DC-DC parts together.

Package and thermal path

SiC losses concentrate at the die and the package thermal stack. Before you accept a "drop-in" alternate:

1. Confirm the package outline and pin assignment against the PCB footprint
2. Compare Rth(j-c) and the recommended heatsink or cold-plate interface
3. Check whether the alternate needs a different gate resistor or RC snubber
4. Re-check EMI filter assumptions if switching speed differs

Module footprints such as EconoDUAL-style packages are especially unforgiving of "similar" substitutions.

Gate drive: the usual RFQ miss

Ask your design owner for the intended Vgs(on) / Vgs(off) before purchasing. Some SiC MOSFETs are rated for a positive on-voltage that is lower than older silicon habits, and some applications use a negative off-voltage to improve noise immunity. Ordering a device your existing driver cannot drive correctly is a field-failure risk, not a purchasing win.

If the BOM also includes isolated gate drivers or digital isolators (for example TI ISO7741), keep those part numbers on the same RFQ so voltage ratings and creepage stay consistent.

RFQ fields that reduce rework

| Field | Why it matters | |---|---| | Full MPN | Package and grade live in the suffix | | Quantity breaks | Reel and tray pricing differ | | Packaging | SMT lines need the packing your process uses | | Condition | New sealed vs pulled modules are different risks | | Date code rule | Power parts in harsh environments often have tighter limits | | Documents | CoC, RoHS/REACH, and any automotive PPAP if required | | End use / destination | Some power modules ship into regulated programs |

Use the RFQ template when that article is live, or request a quote / Request a Chip with the full BOM.

Comparing SiC quotes

Rank quotes on:

• Exact MPN and package
• RDS(on) and thermal figures at your temperature, if the supplier restates them
• Lead time and MOQ
• Document set
• Landed cost including shipping to your country

Do not pick solely on the lowest unit price for a "1200 V 20 mΩ class" description. That description is not a part number.

Bottom line

Buying Infineon CoolSiC, Wolfspeed or ST-related power parts cleanly means locking package, gate-drive needs and the full ordering code before you send the RFQ. Treat SiC like a designed-in semiconductor, not a commodity FET, and your quotes will be faster and safer to release to production.