Replace electrolytic caps with tantalum caps

Using Arduino General Electronics
1

Hi,

I have realized a prototype which uses 3 electrolytic capacitors:

  1. The first is at the output of a DC-DC boost converter (TPS61090RSAR): 100uF

  2. The second is at the input of an ADC converter: 4.7uF

  3. The third is parallel to a LED used in a sensor (suggested by the sensor manufacturer. Likely to make the voltage stable): 220uF

I am designing the PCB using SMD components and I would like to replace the electrolytic capacitors with tantalum capacitors of the same capacity.

As far as I know this should be possible.

Can someone confirm this? Are there precautions?

Thank you in advance.

2

For my customers, the difference is price. All else works the same.

Paul

3

Why do you want to use tantalum capacitors?

4

Maybe worth reading this:

Personally I've never seen a tantalum go bang, whereas I have seen an Al cap burst (but that was stupidity
of mine getting the polarity wrong)... Traditional Al electrolytics don't pose a fire risk though, its a steam
explosion/bursting

5

I had good sized tantalum capacitor on a breadboard that was rated for something like 8 V, without thinking about it, I changed power supplies and gave it 12 V (which was fine for all the other components) and after a few minutes the thing ignited. It was quite a surprise. Of course the same could be said for an electrolytic popping but the ignition was a bit more disturbing to me. Of course it was down to my own own dumb mistake but I've been a bit more wary of using them since.

6

Tantalums have better high frequency performance but they cost more. They are commonly used in switching converters I.e. the first listed application. There's probably no advantage in applications 2 and 3, but they'd work ok.

7

fab64:
I am designing the PCB using SMD components and I would like to replace the electrolytic capacitors with tantalum capacitors of the same capacity.

tantalum capacitors are a kind of 'electrolytic' capacitor anyway, right? But just no liquid runs out of them.

8

Thank you all.

@polymorph: they are smaller than SMD electrolytic counterparts

@MarkT: very informative reference material

I'll go with the tantalum capacitors double checking the voltage rate and increasing it a little bit more. Just in case. I don't want my customers catch fire!

9

fab64:
I'll go with the tantalum capacitors double checking the voltage rate and increasing it a little bit more. Just in case. I don't want my customers catch fire!

That is certainly a good idea. Ample voltage safety margins and trusted sources, if you want to sell them.
I recommend that test overvoltage and reversed polarity yourself. They do fail pretty spectacular and I think everyone using them should have seen it live at least one time. Expect something like a tiny firecracker (the ones that come in sheets on a fuse) for smaller capacities. Keep your distance and maybe wear eye protection.