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High dielectric constan caps, some weirdness

For me that's simple. There are only three options and it's up to the manufacturer:

a. It's in the datasheet. That would be the proper solution.

b. I pester the heck out of the support stuff. Just done that in order to complete an aerospace project. This can easily swallow more than one manhour at the manufacturer to dig out all the stuff that's missing in the datasheet.

c. Worst solution, rarely happens but does: Manufacturer responds that I won't get more data. Then I walk. The old American saying, "If you don't take care of your customer, somebody else will".

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Regards, Joerg

http://www.analogconsultants.com/
Reply to
Joerg
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Au contraire. One of the mfgs did suggest a tantalum series where we'd have gotten the same capacitance in the same size but without capacitance drop at higher bias. One peek at the leakage data thwarted that, IIRC it was 3uA. Now that is guaranteed not to work, plus I do not like to use tantalums.

In a proper datasheet they state insulation resistance. Now how could a

22uF cap possibly not work in this application if it's spec'd in the Gohm range?

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So, since I don't believe you on this one I just took a 1uF X7R out of the bin, charged it to 10V, disconnected it, left it on the bench, waited 40 seconds, measured -> 9.9V. Good enough, I'd say :-)

--
Regards, Joerg

http://www.analogconsultants.com/
Reply to
Joerg

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Did you check it at temperature?

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I miss the days of having our own "Purchasing Dept" WITH properly WORDED purchase contracts: "Shall meet the spec, else supplier is liable... then there's a long diatribe of reimbursable damages!

Reply to
Robert Macy

Then you'd probably all lose your jobs because none of the big guys will sign off on that :-)

--
Regards, Joerg

http://www.analogconsultants.com/
Reply to
Joerg

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No, just at 75F. I could pre-bake it but got too much work for that right now. IIRC the minimum insulation resistance drops by a factor of

5-10 when you go to 200F. I'd never run anything that hot and even that kind of drop would not be a concern. 
--
Regards, Joerg

http://www.analogconsultants.com/
Reply to
Joerg

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they used to. we actually had $100,000 worth of stock shipped back at supplier's expense. didn't meet spec.per purchase contract.and price was reduced for delay.

now the spec sheets even say "can change at any time, without notice" Words used to mean something.

Reply to
Robert Macy

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haha. I should used that instead of normal time units.

Reply to
Cydrome Leader

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