Re: [N8VEM-S100:5177] Tantalum capacitor replacement?

[David Riley <frave...@gmail.com>]

On Sep 9, 2014, at 9:33 AM, Vince Mulhollon <vincemu...@gmail.com> wrote:

> I've occasionally wondered why tantalums aren't vented like electrolytics, at least to minimize the explosion.

My recollection is that it's because the tantalum electrolytic material is a wet material.  A lot of the failure modes of the tantalum caps (particularly the high ESR) come from the electrolytic material drying out, which would be accelerated by vents.  However, given the choice between that or explosive decomposition, I think I'd take a third choice and find a different cap for something I wanted to last more than a few years.

These days, in addition to the niobium caps I mentioned (which are too new, IMO, to really determine if they'll have the same problems), there are aluminum polymer electrolytic caps.  They're usually intended as a drop-in for standard aluminum electrolytics, so the form factor will probably be all wrong if you're trying to replace tantalums, but they're a lot closer to tantalums in terms of nominal ESR without a lot of the associated problems (particularly regarding derating of the operating voltage).


- Dave