Hi all,
I have a general question about mosfet current capability.
I want to build a load and I was choosing a mosfet. Wanting to go big, I picked "2SK2698" (salvaged from somewhere) - it's huge, I mean physically, and it provides ID = 15A and IDP. = 60A. Then I realized that even smaller mosfets (standard sized ones) provide (much) higher currents; this particular one is unbelievable: NCE8580 - ID = 80A and IDP = 320A.
My questions:
1. Why the huge one (double the size, including leads) offers so small/average current compering the standard sizes?
2. How can "standard sized" NCE8580 withstand 80A? As per AWG table, 80A need 20mm2. I know, it's a solid metal but still.
What am I missing here? What is the logic/secret behind?
3. By the way, I constantly struggle to define proper wire size (AWG) for individual current values (generally) - could you please recommend me good source (the information around the Internet differ by hundreds of per cent ... )?

Thank you all in advance!
BR,
j.

 

The 2SK2698 is much higher voltage.

When thinking size...think wattage, the Rds(on) is also critical to the power dissipated in the device. (When being used as a switch)

It's not an absolute just a generalization.

 

For your wire size question, the devil is in the details. You need to look for what the specifications are that the table is for. It might be for a particular temperature rise. It might be for wires in a plenum or other constrained environment, as opposed to free air. It might be for a particular insulation material. It might be for copper versus aluminum or for stranded versus solid. It might be spec'ed for a max voltage drop per some reference length.

 

There is a wire rating tables in NFPA79, of which there is a downloadable copy out there the last time I looked.

 

I want to build a load

If you are going to use these as a load to dissipate power, you need to look at dissipation and safe operating area rather than just current.

 

If you are going to use these as a load to dissipate power, you need to look at dissipation and safe operating area rather than just current.

Hi Bob,
It looks like I would have burned in a minute using the big boy... I didn't consider (know about) the safe region. In this case, the small one (NCE8580) is much more suitable (surprisingly for me, considering the size).
Anyway, thanks for saving my circuit/house/life ! I am going to learn a bit more about mosfets...
BR, j.