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DragonPetter
Feb19-11, 07:46 AM
I know that using diodes in parallel is generally a bad design practice since you will have run away current in one of the diodes since they are not necessarily matched exactly.

But is it safe to use diodes in parallel if they're designed as a common cathode part?

this is an example:
http://www.onsemi.com/pub_link/Collateral/MBRD620CT-D.PDF

So is it safe for me to use the 2 diodes in the package in parallel?

Thank you
Fish4Fun
Feb19-11, 10:33 AM
Why would you want to use two diodes in parallel? If you need 6A current use something like this:

http://www.vishay.com/docs/94252/94252.pdf

If you just happen to have some of the product you mentioned on hand and want to use them for a prototype it will likely work fine, but if you are designing something, use a single diode.

Fish
Fish4Fun
Feb19-11, 10:33 AM
Why would you want to use two diodes in parallel? If you need 6A current use something like this:

http://www.vishay.com/docs/94252/94252.pdf

If you just happen to have some of the product you mentioned on hand and want to use them for a prototype it will likely work fine, but if you are designing something, use a single diode.

Fish
vk6kro
Feb19-11, 06:33 PM
I know that using diodes in parallel is generally a bad design practice since you will have run away current in one of the diodes since they are not necessarily matched exactly.

But is it safe to use diodes in parallel if they're designed as a common cathode part?

this is an example:
http://www.onsemi.com/pub_link/Collateral/MBRD620CT-D.PDF

So is it safe for me to use the 2 diodes in the package in parallel?

Thank you

Diodes on a common IC can be assumed to be very well matched, so you could put them in parallel.

There won't be any "run-away current" anyway. the problem would be that the diodes would not share the current equally if they were mismatched.

The ratings for this device look optimistic, though.
It is about 0.25 inches square and drops 0.9 volts at 6 amps. That is 5.4 watts.

It is going to get very hot. Hot enough to burn a 0.25 inch square in your fingertip if you touch it.