Tektronix has used tantalums in their equipment since around 1970, usually as bypass caps in an RC circuit with maybe a 10 ohm resistor between supply and cap/load and for timing caps for low-freq/long PW one-shots and timers. Tantalum caps didn't fail any more often than ICs, transistors or diodes. A company like that doesn't intentionally use unreliable components and if they do find that a component is unreliable, will quit using them and issue a modification order to swap out any that come into a service center. In my hobby work, I've never had a tantalum failure.

Dean

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I wouldn't say that; it would be very bad design to rely on the ESR to limit the ripple current.

I haven't had any problems with tantalums. I thought they wer more reliable than electrolytics until I came here. Perhaps it's just that one manufracturer produced a load of poor quality components.

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One guy says he doesn't like how tantalums sound in his system?


That problem has nothing to do with tantalums but rather his lack of understanding what is actually desired in his system (impedance -wise)

The context of our discussion is around the reliability aspect. Performance is what seems they are after. Impedance is impedance whether is comes from AL-elec or Tant-elec or ceramic for that matter.

 

up for more

 

No, you've got it wrong

Tantalum capacitor has an ESR ten times better than that of electrolytics


On a previous comment by someone else, informities that develop/part of the manufacturing process actually 'self fill' and hence they never loose capacitance, therefor its not just their shelf life, but their operating life that is considered 'infinite'

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You misread my statement, electrolytics have a higher equivilant series resistance, so in pulse charging and discharging applications they will self limit their own charge/discharge rates because of the inherant resistance. A tantalum cap because of it's better (lower ESR) doesn't 'self limit' it's current. EL's and tants might have similar ripple current ratings, but a significantly lower ESR for the tant would make it more prone to self destruction from instantanious pulse heating when it was used in a low impedance situation (such as a filter cap which is usually connected via a VERY low ohmic connection to ground) Out of every post I've read so far that's the only thing that makes sense to me. If someone knows something else they better start spilling the beans =>

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I wouldn't agree, if the ESR is lower then the power dissipation will also be lower and it's the job of the designer to ensure that the ripple current isn't exceeded which isn't a hazard in 99% of applications anyway.

Overcurrent is only a probelm when a capacitor is used as a mains frequency smoother in a power supply, when connected in series with a speaker in an audio amp or used in power factor correction - a 10µF capacitor isn't going to have it's ripple current rating exceeded however low its ESR may be.

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I just thought I'd post since this is so old and Nigel could be misleading people looking for answers about tantalums.

Maybe back when dinosaurs roamed the Earth when you were using them they were unreliable, but today they are very reliable. No less than five times have I taken apart a device certified for use in life support applications to find them littered with tantalums. I used them in college for statistics experiments to verify the claimed reliability of the manufacturers only to find every single time that it was right. Trials were conducted over several months with varying as well as extreme temperature and voltage gradients.

I even attached a picture of an RC receiver using tantalums. This module has been in service for several years in the bitter cold and blistering heat. I'd say it was a fluke if I knew as little about tantalums as you seem to but the reality is that they are better devices than their aluminum electrolytic counterparts in many applications. Your inability to get past your ego is quite irritating when all of the facts point the other direction from your opinion. That is not how science works.

/rant

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I Agree, I use Tantalums in almosty all the projects on my website and have Never had a probem with them.

Gary

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Me three! I hate aluminum electrolytics. I have had a lot of circuit failures due to leaky electrolytics.

 

I seem to be using electrolytic more often then not now days as they are cheaper and the AUD -> USD has been pitiful for quite some time

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