Can someone please explain me the main characteristics of tantalum capacitor? I have been trying a lot to find out something which I can easily understand as a newbie but didn't find anything yet.
Any link something like this An Overview on Tantalum Capacitors - DERF Electronics would also be helpful.
Awaiting your response.
Thanks!
Any link something like this An Overview on Tantalum Capacitors - DERF Electronics would also be helpful.
Awaiting your response.
Thanks!
The main characteristic is that the manufacturers do not supply an hours life rating. Ask for one for an aluminum electrolytic from newark or digikey, no problem. Ask for one for a tantalum, - - - - - -
So installing one is a dice game. The manufacturers don't stand behind them, they just sell them.
They are banned in aircraft avionics, I believe I read.
9 of the 10 in my H182 organ failed. 2 of 2 in my ST120 had popcorn noise. OTOH 80 of 80 in a 1980 Allen 300 organ are good. So if you have an incoming inspection department with sufficient equipment to do your own life test, you may be able to source some good ones.
Because they are not wound, they have lower inductance than aluminum electrolytic cap. They are formed from paste. May have some use in radio frequency electronics: in products that are designed to be obsolete in 2 years, like cell phones. They are especially tiny, to fit in pocket products.
No point in using them in audio, IMHO. As I've had to replace >400 aluminum electrolytics over the years, and 50 or more tantalums, I prefer to use caps that come with a >7000 hours service life rating. I replaced e-caps in my ST70 4 times. Film dielectric is nice where it will fit. I prefer to listen to music or play a new piece on my organ to replacing expired caps.
So installing one is a dice game. The manufacturers don't stand behind them, they just sell them.
They are banned in aircraft avionics, I believe I read.
9 of the 10 in my H182 organ failed. 2 of 2 in my ST120 had popcorn noise. OTOH 80 of 80 in a 1980 Allen 300 organ are good. So if you have an incoming inspection department with sufficient equipment to do your own life test, you may be able to source some good ones.
Because they are not wound, they have lower inductance than aluminum electrolytic cap. They are formed from paste. May have some use in radio frequency electronics: in products that are designed to be obsolete in 2 years, like cell phones. They are especially tiny, to fit in pocket products.
No point in using them in audio, IMHO. As I've had to replace >400 aluminum electrolytics over the years, and 50 or more tantalums, I prefer to use caps that come with a >7000 hours service life rating. I replaced e-caps in my ST70 4 times. Film dielectric is nice where it will fit. I prefer to listen to music or play a new piece on my organ to replacing expired caps.
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Tantalum caps have a low ESR and get used as bypass capacitors on chips that can switch or pull lots of current very quickly.
I haven't seen any tantalum cap with ESR lower than in actual low-ESR aluminium. Though in general, it is lower than in general use aluminium caps.
But since that time we have low-ESR electrolytes and ultra-low ESR polimer caps.
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You may have a look at notebook mainboards where you will find a lot of smd tantals in the power supply section.
Lots of people didn’t bother to read application notes for tantalums. You really need to uprate the voltage rating. Say for 15v rails use caps rated for 35v. Now polymer caps are far superior and should last forever.
Have you read and digested all 8,000 words on Wikipedia? Wikipedia is not absolutely true, but is sometimes an excellent overview of a subject. This has 76 references, mostly outside Wikipedia, for cross-checking.
Some types of Tantalum have no known wear-out (lifetime) mechanism. They may have a sudden vaporization mechanism but not predictable.
Up until the 1970s most Aluminum e-caps were poor quality and the far more expensive Tant e-caps were better in a few ways. Tolerance. Leakage. We find Tants in a lot of 1970s audio. We find them by the smoke, random vaporization. For several reasons the Aluminum e-cap makers became very motivated to make better Al e-caps. Today I do not know any reason go Tant in audio except a few NEVE consoles, and then maybe as much resale value (ha!) as the possibility of hearing different cap-types in adjacent channels.
Some types of Tantalum have no known wear-out (lifetime) mechanism. They may have a sudden vaporization mechanism but not predictable.
Up until the 1970s most Aluminum e-caps were poor quality and the far more expensive Tant e-caps were better in a few ways. Tolerance. Leakage. We find Tants in a lot of 1970s audio. We find them by the smoke, random vaporization. For several reasons the Aluminum e-cap makers became very motivated to make better Al e-caps. Today I do not know any reason go Tant in audio except a few NEVE consoles, and then maybe as much resale value (ha!) as the possibility of hearing different cap-types in adjacent channels.
To astoufffer's point - The published voltage rating of a Tantalum is ambitious at best.
Back in the 80s I had designed a test system with quite a few boards containing tantalums as bypass. A tech slipped with a probe and all 125 tantalums popped like firecrackers.
Back in the 80s I had designed a test system with quite a few boards containing tantalums as bypass. A tech slipped with a probe and all 125 tantalums popped like firecrackers.
We had something like that happen, but no one slipped. Just $10,000 of hardware ruined
because of crap parts, used per spec, bursting into flame.
because of crap parts, used per spec, bursting into flame.
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The problem with Tantalums (at least the dipped variety back in the day) in a nutshell -
Tantalum: Hey, I'm super low ESR!
Inrush current: OK, here I come...!
Tantalum: <surprised Pikachu face> 😱
Tantalums may have low ESR, but they're also tiny. The amount of inrush current they'd handle actually wouldn't be all that great, and it took uprating the voltage (= bigger cap) to compensate for this problem.
Also, they really, really hate being reverse-biased, apparently.
Besides, conflict minerals and stuff.
Tantalum: Hey, I'm super low ESR!
Inrush current: OK, here I come...!
Tantalum: <surprised Pikachu face> 😱
Tantalums may have low ESR, but they're also tiny. The amount of inrush current they'd handle actually wouldn't be all that great, and it took uprating the voltage (= bigger cap) to compensate for this problem.
Also, they really, really hate being reverse-biased, apparently.
Besides, conflict minerals and stuff.
I used to have to troubleshoot boards that had 50 or so tantalum caps and one would be shorted. Gave up trying to find it with a bench meter and put the thing on a current limited supply. Turn up the current slowly while touching each one. You'll find the shorted cap with enough current.
Companies are still recommending tantalums today. The LMH6321 datasheet talks about requiring them. Don't understand why though.
Companies are still recommending tantalums today. The LMH6321 datasheet talks about requiring them. Don't understand why though.
Polymer tantalum are pretty good. The capacitance / volume may be better than Al polymer caps, not sure, depends on voltage rating and what you choose for derating. The ESR is a little higher, which can be a good thing, actually. I think modern, high quality tantalum caps will be extremely reliable and long lived. There's really no need to use them, though, as sgrossklass points out. I see more and more boards with no electrolytic capacitors of any type, only MLCCs.
Tantalum (Ta) caps designed for switchmode DC-DC converters can have very low ESR and high ripple current carrying ability. The bead types are fragile and are best left to timing capacitor or light bypassing applications.
They can be unreliable.
Havent used them in about 40 years.
They were popular in the 1980's.
We used them in logic circuits a lot.
1 10uf tantalum to about 5 100nf's poly's.
Seen a couple of youtube motherboard video's where tantalums have gone short circuit.
In my experience of repairing professional audio kit, they seem to act unpredictably going short short circuit and I don't understand why they continue to be used.
I do wish they were not used and I take them out when I come across them.
Mike
I do wish they were not used and I take them out when I come across them.
Mike
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