Tantalum Capacitor Failure
Tantalum Capacitor Failure
(OP)
Anyone have any information / experience relating to tantalum capacitors failing short? Anything on manufacturing process or circuit transients causing the failure would be greatly appreciated.





RE: Tantalum Capacitor Failure
The failure mode tantalum capacitors is to short. Some varieties of tantalum capacitors are made with an internal fuse for circuits that cannot tolerate a short.
RE: Tantalum Capacitor Failure
The reason for the reverse polarity is often that one of the supplies (usually the negative) gets "overridden" by the positive (which usually is the heftier one) and kills the tantalum capacitors.
It is difficult (impossible) to avoid this in many circuit types - especially if there is some sort of power stage involved. If you think that this is the problem (you should check the voltages with a memory scope at turn-on and turn-off) the easiest solution is to add diodes parallel to the supplies (I don't bother to mention which polarity they shall have
RE: Tantalum Capacitor Failure
The fix is low ESR caps or paralleling standard ESR caps.
RE: Tantalum Capacitor Failure
Several years ago we were supplying equipment to a Japanese company and they insisted that all the tants be replaced by ordinary electrolytics and solid dielectric capacitors. This was a huge task, but it was a big order so we did it!
RE: Tantalum Capacitor Failure
That is, do not for instance use them in power supplies for ripple reduction. At least not if the rush-in/out current at any time can be greater than, say, 500 mA.
You can get tantalum based capacitors, which allow for a larger current, but for the small epoxy pearl things:
Keep the current low.
RE: Tantalum Capacitor Failure
Measurements seem to indicate that there isn't a huge inrush current, but something is causing it to blow from time to time
RE: Tantalum Capacitor Failure
I=C*dV/dt ?
RE: Tantalum Capacitor Failure
The cap at the fet gate is possibly there to reduce the turn-on time. Good thing.
The maximum current peaks are usually documented in the spec sheets.
What's the voltage rating of your cap? Have you tried one with a higher voltage rating?