| Electronics > Projects, Designs, and Technical Stuff |
| Good low leakage electrolytic caps? |
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| cvanc:
Hi all- So I use and like the Nichicon UKL series of low leakage electrolytics. These have served me well but I am curious to know of other brands/series that I should also consider. Anyone got other types they like? Thanks. http://www.nichicon.co.jp/english/products/pdfs/e-ukl.pdf |
| cvanc:
Answering myself here... I found the Vishay/Sprague TVA 'Atom' electros are low leakage, although they are available only in axial form factor https://www.mouser.com/datasheet/2/427/tvatom-266625.pdf Vishay/Sprague also has large beer can computer grade caps that are low leakage. This isn't what I'm looking for but here's the datasheet https://www.mouser.com/datasheet/2/427/36ddedx-239977.pdf I haven't found any other vendors playing in this space, which kind of surprises me. |
| Kleinstein:
With electrolytic caps leakage is hard to separate from dielectric absorption. At least it is a very lengthy procedure. This a good argument to avoid specs that are too tight in this area. Not many applications need really low leakage electrolytic caps (maybe buffering small batteries) so not that much demand. |
| MagicSmoker:
Low leakage and electrolytic capacitor don't really go together, but given that leakage goes up with temperature, capacitance and percent of rated voltage applied, you can obviously arrange circuit conditions - if not environmental - in your favor: use the smallest capacitance with the highest voltage rating possible. Also possibly relevant is that the aluminum oxide dielectric tends to degrade after some time (undefined) without a bias voltage applied, so leakage tends to be highest in the first few seconds to minutes after voltage is reapplied. Other than that, consider a different dielectric is minimizing leakage is really important. |
| Obsolete units:
If you need really low leakage, at 1uA or less, wet tantalum takes a lot of beating. But you need deep pockets - the Vishay SuperTan series are hundreds of dollars *each*. Carefully selected aluminium electrolytics will reach that sort of leakage if left with a stable voltage for a day or two, and orders of magnitude less cost. Jim Williams Linear Tech Apps note 124 describes a low noise low frequency technique that uses a 1300uF 30V wet tant that costs over $400 - but he needs nA leakage current. And even that cap takes 24 hours to charge |
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