How to find the right TEMPFET Transistors AI guide
Written by an AI model from its trained knowledge.
What the AI looks for in TEMPFET Transistors
- What 'TEMPFET' means
- Treat it as a power MOSFET with an on-chip temperature sensor or overtemperature shutdown, a term that originated with Siemens/Infineon Many original TEMPFET part numbers are legacy, so a replacement is usually found among current protected-MOSFET families.
- Protection behavior
- Check whether thermal shutdown latches off or restarts automatically, and whether current limiting and overvoltage clamping are included Latching and auto-restart parts behave very differently in a fault and are not interchangeable in a system.
- High-side vs low-side
- Use low-side protected FETs between load and ground, and high-side smart switches between supply and load Protected switches are built for one position, and the wrong topology will not switch or protect correctly.
- Input drive level
- Confirm the part turns fully on from the controller's logic voltage, whether 3.3 V or 5 V Many protected FETs need the gate pin to also power the protection circuit, so they can misbehave on weak or low-voltage drive.
- Voltage class and on-resistance
- Choose a drain-source rating above the supply plus inductive clamp energy, and an on-resistance low enough to stay within the thermal budget at load current In automotive and 24 V industrial loads, load dump and inductive kickback set the real voltage requirement.
Brands that matter
- Infineon: Originator of TEMPFET; its current HITFET low-side and PROFET high-side protected switches are the usual successors.
- STMicroelectronics: VIPower OmniFET fully protected low-side MOSFETs and high-side smart drivers.
- onsemi: Self-protected low-side MOSFETs for automotive and industrial loads.
What to avoid
- Replacing a protected FET with a plain MOSFET of the same rating when the system relies on its thermal shutdown
- Assuming any 'smart' switch with matching pins has the same fault behavior or diagnostic output
- Unmarked surplus parts with no datasheet to confirm the protection features
Questions
Is a TEMPFET the same as Infineon's HITFET or PROFET?
They belong to the same idea of a MOSFET with built-in temperature protection. HITFET is Infineon's protected low-side family and PROFET is its high-side smart switch family, and both are where most TEMPFET replacements are found today.