Capacitance versus voltage for X7S caps?

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Reply to
Spehro Pefhany
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Shazam! Thanks, this stuff does look quite good. If this is true I wonder why on earth the others don't advertise it properly. But it's not really a surprise since many datasheets are seriously dumbed-down these days.

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Regards, Joerg

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Reply to
Joerg

Do you have access to the EIA-198-1-F, EN 132100/ IEC 60384-10 etc?

Looks like voltage coefficent _limits_ are covered by the sub-class under EN 132100/ IEC 60384-10 at least, but I don't see the sub-class

2-letter code listed in the TDK datasheet.
Reply to
Spehro Pefhany

Unfortunately I don't have access to those. But standards are sort of iffy in the capacitor business. For example, I found two vastly different heights for the supposedly standardized 2220 SMT-package. One listed 2.2mm and would fit in our situation, the other listed 0.160" and would be way too tall.

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Regards, Joerg

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Reply to
Joerg

I know that the rating system of ceramic capacitors allow "X7S" but i have never seen (anything)(anything)S even sold... So why the question?

Reply to
Robert Baer

If TDK supplies a chart for the device showing capacitance change vs applied voltage, for modeling or other purposes, I think you should see this as the equivalent or better of a text line stating % over a voltage range and not bitch about it.

The EIA capacitance designator standard does not specify voltage dependence, but the dielectrics capable of X7 stability are also less voltage dependent.

EIA STANDARD RS 198

lowest TEMP - 1st designator

- 55 °C - X

- 30 °C - Y

  • 10 °C - Z

highest temp - 2nd designator

  • 45 °C - 2
  • 65 °C - 4
  • 85 °C - 5
  • 105 °C - 6
  • 125 °C - 7

tolerance - 3rd designator ± 1 % - A ± 1.5 % - B ± 2.2 % - C ± 3.3 % - D ± 4.7 % - E ± 7.5 % - F ± 10 % - P ± 15 % - R ± 22 % - S

  • 22 %/-33 % - T
  • 22 %/-56 % - U
  • 22 %/-82 % - V

RL

Reply to
legg
[...]

Sorry if a dumb question, but are those tolerances the worst case extremes over the temperature and voltage ranges?

Thanks,

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John Devereux
Reply to
John Devereux

The tolerance is over the temperature range indicated, without any other influence considered.

RL

Reply to
legg

Nope, it won't :-)

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Regards, Joerg

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Reply to
Joerg

And that's not telling anything about voltage tolerance. The temp curves are usually in the datasheets, voltage graphs aren't anymore :-)

Dumbed-down datasheets are even a problem in semiconductors. There are "new and improved" datasheets of PIN diodes where carrier lifetime is no longer listed. Luckily I hang on to the old ones. About 10ft shelf space worth of data.

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Regards, Joerg

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Reply to
Joerg

...in which case that 0.1 height restriction gets blown.

Reply to
Robert Baer

The TDK graphing utility is really quite good. Perhaps you might encourage this kind of data service by buying only those parts for which info IS provided.

TDK will even plot multiple selections on the same axis - just be very general about your initial selections - voltage, body size and maybe tempco.

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I'm sure they're not the only vendor still supplying useful data. Just be sure to label an store it for easy retrieval, once obtained, to save trouble the next time around.

RL

Reply to
legg

-> "No results were found" :-(

I could try over and over again to make it spit out a capacitance over voltage graph, on the client's nickel. Or just move on to another brand ...

Why can't they simply put it in the datasheet like it used to be done in the good old days? To be honest I am not very fond of online tools, they are often frustrating. For example, National's WebBench told me numerous times that my switcher could not be designed. All of them went into mass production :-)

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Regards, Joerg

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Reply to
Joerg

Works fine for me - quite nice, I agree it should be in the datasheet.

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John Devereux
Reply to
John Devereux

Maybe I am doing something wrong with the search input fields. How do you get the capacitance versus voltage graph for the TDK capacitor with the part number C4532X7S2A475M ?

[...]
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Regards, Joerg

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Reply to
Joerg

Drop the last letter or use C4532X7S2A475K

I found this by specifying a characteristics search in multilayer capacitors >0.1uF, then specifying tempco (x7s) and series (4532)

If you select only a voltage range, impedance range and frequency, you will be offered a window allowing comparison of all suitable part numbers individually or on the same graphs, regardless of body size or tempco or class. This is the easiest way to see X7R and X7S offerings, side by side.

RL

Reply to
legg

=20

that=20

graph=20

That is relatively easy. Polystyrene, polyethylene, or=20 polyethylenterephthalate [PET / Mylar] are normal materials=20 of choice. Of course if you have atypical size constraints=20 you may have real difficulty obtaining any parts of reasonable=20 price.

Reply to
JosephKK

very

over

Since you stated 4.7 uF @ 100 V i looked in the medium voltage list, under 4.5mm x 3.2mm [EIA 1812] and there is at the bottom of the list.

-60 % at 50 V.

Reply to
JosephKK

Ok thanks, now I got it. Strange that the tool doesn't recognize their own part numbers. Still, why do they stop at 50V while it is a 100V part?

I really prefer the old datasheet method. Faster, and you can store it as a document for ECO release. An online tool result doesn't necessarily cut the mustard when the agency guys audit my designs.

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Regards, Joerg

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Reply to
Joerg

But the graph stops at 50V while it's s'posed to go to 100V ...

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Reply to
Joerg

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