Electronic – Schottky Diodes in parallel

schottky

I was looking at a reference design and I saw a symbol I didn't recognize:

ref design

So I looked up the part. It's a dual Schottky rectifier like this:

enter image description here

What is the purpose of having two diodes in parallel in this case?

Thanks

Best Answer

The current is split between two junctions, thus slightly reducing thermal dissipation on each one and improving reliability/MTBF. Since the diodes are in the same package, the risk of unbalanced current is likely to be very low, so considerations about paralleling discrete diodes don't apply.

Furthermore, SOT23 double diodes seem to be very common and somewhat standard in larger firms (thus less expensive). Given that connecting together anodes of a double diode doesn't involve a significant increase in the probability of failure, it makes sense to do so instead of not.

However, it is important to note that such approach leads to double leakage current. This has to be considered for applications where leakage current can raise any problem.

Take a look at this German forum topic, about BAT54C (very similar to BAR43C, indeed): Warum zwei parallele Dioden? (Google translation)

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