Hi
I need 4 diodes for a bridge rectifier. I have narrowed it down to this diode:
It has a typical forward voltage of 1.05V at 5A
But this one has almost the same forward voltage at that current but is rated for 3A max
What is the difference since the case is the same and the thermal resistance also?
Thanks
Klaus
The die is smaller for 3A. Consequently the price should be lower.
--
Boris Mohar
The second diode isn't rated at the same current as the first. The data sheet gives the forward voltage at 2.5 A.
-- John
Well, yes. But what caught my eye was that the typical curves at 5A is almost identical and the thermal resistance junction to lead is also simelar. Since the powerloss then is the same, the junction temperature should then also be the same.
I would assume (assumptions is the mother of all fuckups), that the rating would then be identical. Ofcourse it could be an issue of maximum ratings that have larger spread on the 3Amp version than the 5A version. The forward voltage I qouted was typical data
Regards
Klaus
The 5 A diode shows theta J-T of 10 K / W, while the 3 A unit shows theta J-L, junction to lead, the same thing, of 13 K / W. That's quite a bit higher, although not quite 5/3.
-- John
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