I wonder if the OP tested the fan to ensure it did not exceed the MOSFETs avalanche ratings?
Sorry, I thought you meant measuring the voltage between 12V and Drain. I'm no longer using any code right now, just troubleshooting with 5V and 12V as Gate, 12V as Drain and load (as per my diagram). I have no problem testing with the MOSFETS as I have many of both types.
Results are the same with any 12v fan, light bulb. I didn't try LEDs yet, seemed too much effort to put so many in series.
Measurments from both MOSFETS show this: 11.24V Drain to Source, if the Gate is at 0V.
the IRL540, if Gate is 5V, Drain to Source is 9.74V
The IRF520, if Gate is 5V, Drain to Source is 0.01V
the IRL540, if Gate is 12V, Drain to Source is 0V
The IRF520, if Gate is 12V, Drain to Source is 0V
the IRL540, if Gate is 3.3V, Drain to Source is 11.05V
The IRF520, if Gate is 3.3V, Drain to Source is 11.03V
Definitely says the MOSFET is NFG (Not functioning good).
Your IRL540 is either damaged, mismarked or counterfeit.
Do you have many of the IRL540's?
Yep, i have a pack of 10, all same behavior. They are IRL540N -P837D -6k8h , from International Rectifier apparently, same as the IRF520N.
I have 5 IRF520N and they all work identically to each other as well.
So I guess i can just scrap all my IRL540N, as they don't behave properly.
Thanks!
If you purchased them from a US reputable source I would go back to them. Not only for you but for others that have not yet purchased them.
If eBay seller, scrap and purchase from a different source.
"the IRL540, if Gate is 12V, Drain to Source is 0V
The IRF520, if Gate is 12V, Drain to Source is 0V"
Looks like the IRL540s are mislabeled, what if the gate voltage were 8V?
If you didn't buy them from a reputable electronics supplier they will be counterfeit almost certainly these days.
I doubt the IRL540's are mislabeled. These are run on a high volume production run with automated testing keyed to the part number.
My guess is counterfeit. Where they take a high volume of some cheap/inferior TO220 Mosfet and mark it with any number of different partnumbers.
Thanks everyone. So if I can conclude this discussion, my thought was right that the specs was what I was looking for, but the parts are most likely not meeting specs and are probably counterfeit.
I'll use the IRF520, since they work. I'll be doing PWM on them. I hope I don't generate too much heat, but doubt it.
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