Good quality tantalum caps ?  - Page 1
Forum section: electronics / beginners

author: l3gi0n
author_rank: Regular Contributor
timestamp: October 18, 2021, 01:01:16 am
content: I need 330uF 2.5v tantalum caps...I want to replace OE128 NEC Tokin caps..I am currently looking at these:https://www.ebay.ca/itm/232369804400?hash=item361a51d470:g:nsAAAOSw8-tWXfBGAre these caps ok ? or should I look for something more durable ? if so, please make your recommendation...Thanks

author: rsjsouza
author_rank: Super Contributor
timestamp: October 18, 2021, 01:10:53 am
content: Well, depends on the application. Ebay is not a very trustworthy place to source components, but you may have some luck. I did a quick search on Mouser, Digikey and found these eBay capacitors are about half price of the ones from the authorized distributor - in my opinion, I don't think the price difference warrants going the eBay route, but YMMV.The mouser search:https://www.mouser.com/Search/Refine?Keyword=330uf+tantalum+2.5v

author: l3gi0n
author_rank: Regular Contributor
timestamp: October 18, 2021, 01:50:47 am
content: OK, one more questionWhat is the shelf life and operational life of tantulum capacitors ?

author: andy3055
author_rank: Super Contributor
timestamp: October 18, 2021, 02:01:36 am
content: Why all the way from Portugal?https://www.ebay.ca/itm/191199058364?epid=1601713637&hash=item2c845a19bc:g:LKIAAOSwbY5dwTVL

author: l3gi0n
author_rank: Regular Contributor
timestamp: October 18, 2021, 02:12:20 am
content: The guide I am following says that I should use 330uF 2.5V tantalum capacitors....There are zillions of different specs for tantalum caps besides farads and voltage....should I worry about them ?

author: perieanuo
author_rank: Frequent Contributor
timestamp: October 18, 2021, 08:03:52 am
content: yep, don't buy from ebayyou need quality, buy farnell&co otherwise it's gambling

author: wraper
author_rank: Unknown
timestamp: October 18, 2021, 08:12:12 am
content: They should be LOW ESR (most of tantalum capacitors are not), ebay listing says nothing about that. You don't necessarily need tantalum capacitors, you may find a better option from Aluminum polymer capacitors. Like SP-CAP from Panasonic.https://na.industrial.panasonic.com/products/capacitors/polymer-capacitors/lineup/sp-cap-polymer-aluminumAlso a larger quantity of smaller caps likely will fit better than 4 330uF soldered under angle.

author: Siwastaja
author_rank: Super Contributor
timestamp: October 18, 2021, 08:31:46 am
content: Capacitor replacement requires very good understanding about the circuit design.Actually, no, capacitor replacement requires you understand the circuitbetterthan the original designers did! Because there must be reason why the parts failed.The original parts chosen by professional designers failed i.e. were unsuitable. What are the chances that some random parts from Ebay with no specifications arebettersuited? You can of course try and with good luck, get a few years more life out of the thing, but tantalums specifically tend to end up in flames when misused.At the very least you need schematics to calculate ripple current and peak inrush current (latter being relevant with tantalums but not most other types), then choose parts rated for these currents in their datasheets. And remember 40-50% voltage derating for tantalums.Generic answer to "is this capacitor good" is, "no". All capacitors are crap, meaning the world of capacitors is full of compromises making it pretty difficult to design with them. That's why professionals get paid for their job (and still manage to do it wrong, quite often).

author: David Hess
author_rank: Super Contributor
timestamp: October 18, 2021, 07:55:53 pm
content: Quote from: l3gi0n on October 18, 2021, 01:50:47 amLow voltage solid tantalum capacitors have no wear out mechanisms. High voltage ones may suffer from crystallization around defects in their dielectric according to NASA.Failure comes from either abuse, or through external mechanisms which cause damage to the capacitor.One way to increase reliability is to reform the dielectric after mounting because it tends to be damaged by strain induced during the soldering process.

author: Stray Electron
author_rank: Super Contributor
timestamp: October 19, 2021, 01:19:12 am
content: David,What voltage do you reform them at and for how long?

author: David Hess
author_rank: Super Contributor
timestamp: October 19, 2021, 03:42:50 am
content: Quote from: Stray Electron on October 19, 2021, 01:19:12 amThey are reformed by applying the maximum voltage that the capacitor is rated for while limiting the current. The actual process may be more complex than this. Doing this forms the dielectric and clears any faults that may have developed during the soldering process.There is some discussionin this videoabout it.Polymer tantalum capacitors do not suffer from this but the polymer conductor may degrade over time, and these capacitors have much much lower ESR so may not be appropriate for all applications.The above does not explain failures in dipped epoxy tantalum capacitors since being leaded parts, they should not be damaged by the heat of soldering. My hypothesis is that humidity and temperature changes over long periods of time cause the epoxy encapsulation to stress the tantalum pellet. Hermetically sealed solid tantalum capacitors never seem to fail this way.If you use solid tantalum parts, then derating the voltage by 50% or more completely removes this failure mode because self healing will not result in thermal runaway. Even derating to 66% should be effective enough. Somewhere I think I have an AVX application note which discusses this but it might have been in the video above.

author: xavier60
author_rank: Super Contributor
timestamp: October 19, 2021, 05:24:33 am
content: I have had better long term results with fitting a bunch of 100uF 6.3V MLCCs. The ones I received measured 80uF.Even MLCCs lose some capacitance with time, so enough need to be fitted.

author: Siwastaja
author_rank: Super Contributor
timestamp: October 19, 2021, 06:59:42 am
content: Replacing other types with MLCCs is prone to cause catastrophic oscillation of control loops and/or ring with parasitic inductance, resulting in voltage peaks or even wrong average voltage of regulators, because they are too low in ESR.Of course this doesn't always happen, sometimes the circuit is stable to near zero ESR in which case lower ESR is only better.

author: l3gi0n
author_rank: Regular Contributor
timestamp: October 19, 2021, 03:16:57 pm
content: I want to change my PS3's NEC TOKIN caps to Tantalum caps...I should use 330uF 2.5v Tantalum caps...Can I use any 330uF 2.5v Tantalum caps ? such as these:?https://www.mouser.ca/ProductDetail/Panasonic/ETPE330MIB?qs=4qgZ1GHix0WhLOtvMiudBw%3D%3D

author: wraper
author_rank: Unknown
timestamp: October 19, 2021, 03:39:04 pm
content: Quote from: l3gi0n on October 19, 2021, 03:16:57 pmProadlizer caps have about 1-1.5 mOhm ESR depending on model. Those caps have 15 mOhm ESR, divide by 4 and you have 3.75 mOhm ESR which is too much. Most likely it will work but it's a downgrade. For comparable performance you would need to mount 10 of those or 4 caps with 4.5 or 6 mOhm ESR like these:https://eu.mouser.com/ProductDetail/Panasonic/EEF-LX0E331R4?qs=APoVD1cryDLdur2dAtdMmQ%3D%3D4.5 mOhmhttps://eu.mouser.com/ProductDetail/Panasonic/EEF-LX0E331R?qs=APoVD1cryDLtPjbZTVuFyw%3D%3D6mOhmAlso these caps have another negative terminal in the middle, so you don't need to mount them under angle.

author: l3gi0n
author_rank: Regular Contributor
timestamp: October 19, 2021, 04:29:28 pm
content: Quote from: wraper on October 19, 2021, 03:39:04 pm(1) I am looking for Tantalum caps...the caps you posted have limited life time.(2) The 4-pack I was about to buy from eBay have an ESR of 25mOHM...and they can replace an OE128 NEC Tokin(though mine are OE108):https://www.ebay.ca/itm/232369804400?hash=item361a51d470:g:nsAAAOSw8-tWXfBG(3) I am looking for a compatible Tantalum cap with a length of 3.5mm ...This way, soldering it would be much easier...

author: wraper
author_rank: Unknown
timestamp: October 19, 2021, 04:39:05 pm
content: Quote from: l3gi0n on October 19, 2021, 04:29:28 pmYour tantalum caps have 2 times lower lifetime and 3 times lower max ripple current spec. You are deeply mistaken if think that tantalum caps have no lifetime rating.QuoteAs I said, those caps have a negative terminal in the middle, so you solder to that. And keep them straight. Like on the photo.

author: l3gi0n
author_rank: Regular Contributor
timestamp: October 19, 2021, 04:49:15 pm
content: OK, just to confirm:I should buy 4 of these for each NEC Tokin cap :https://eu.mouser.com/ProductDetail/Panasonic/EEF-LX0E331R4?qs=APoVD1cryDLdur2dAtdMmQ%3D%3DThe motherboard has 4 NEC Tokins(0E108) 2x on the top and 2x on the bottom, as can be seen here:https://www.psdevwiki.com/ps3/DYN-00xSo I need 16 of the Panasonics...right ?

author: wraper
author_rank: Unknown
timestamp: October 19, 2021, 04:55:45 pm
content: Quote from: l3gi0n on October 19, 2021, 04:49:15 pmYes

author: l3gi0n
author_rank: Regular Contributor
timestamp: October 20, 2021, 12:19:00 am
content: Since my PS3 is the slim version, the NEC/Tokins are 0E108 which are rated 1000uF...Can I use 4x 270uF 2.5v 6mohm caps per each nec/tokin ? something like this:https://www.mouser.ca/ProductDetail/KEMET/T528B277M2R5APE006?qs=sSYV1F9c5cHzT3p55Q8Zag%3D%3Dtheir length is 3.5mm ... makes the soldering a lot easier...are there any other compatible 3.5mms ?

author: wraper
author_rank: Unknown
timestamp: October 20, 2021, 06:32:01 am
content: Quote from: l3gi0n on October 20, 2021, 12:19:00 amYou can use them but their ripple current spec is half of those Panasonic and they are 2 times more expensive. 16 caps will cost you C $70 instead of $34. And will have worse specs.

author: rsjsouza
author_rank: Super Contributor
timestamp: November 23, 2021, 04:59:48 pm
content: Quote from: l3gi0n on October 20, 2021, 12:19:00 amI just replaced a 0D108 on my Samsung laptop with fourEEF-HX0E331R4, which also have similar specs as the EEF-LX0E331R4 mentioned a couple of threads above. I did a thorough search but could not find a more suitable and reasonably priced candidate for that. The low ESR and the high ripple current are the most critical factors, but in my case I also overspec'd the voltage rating (the 0D108 is 2.0V, while the replacements are 2.5V). I also took advantage of the multiples (10x) as the Nvidia adapter on the same laptop also used three 330 µF/4.5 mΩ in parallel.