what does the diode do in a mosfet?


Senior Member
Im looking at the schematic on the data sheet for a IRF540N mosfet. It shows what looks like a zener diode inside the package. What does it do? Is it to absorb back EMF in induction loads?

Here are some notes from IRF<A href='http://www.irf.com/technical-info/appnotes/an-936.pdf' Target=_Blank>External Web Link</a>
For heavy work don't rely on the internal diode alone, use a 1N4004 or 1N5408 or heavy duty (TO-220 package) high speed diode.
A few cents to a dollar or two on a diode could save you 5 to 10 bucks replacing a dead MOSFET.


Senior Member
Thanks guys, thanks Michael for finding the link and posting it.

The data sheet is great Michael, a big thank you.


Edited by - BrendanP on 04/09/2007 09:33:38