WIMA FKP2

[kumiroff]

Hey, guys! Has anyone tested WIMA FKP2 capacitors? How do they behave at frequencies of 10-20 MHz?

 

[lcsaszar]

You can find the impedance diagram here:
https://www.wima.de/en/our-product-range/filmfoil-capacitors/fkp-2/
Probably you'd better use a ceramic capacitor for HF.

 

[kumiroff]

Will they fit here? Or should I still choose mica or ceramics NP0 (C0G)?

 

[rayma]

No, use COG/NPO ceramic types for such small values.

 

[kumiroff]

No, use COG/NPO ceramic types for such small values.

Will MLCC ceramics be suitable? Or do I need a disk one?

 

[HalFoster]

Are C0G's even available in disk? Any C0G will work, just be sure that the rated voltage is high enough for the application and that the lead spacing is correct.

 

[EUVL]

Smallest value of FKP2 is 33p.
47p and 100p are no problem.


Patrick

 

[rayma]

Will MLCC ceramics be suitable? Or do I need a disk one?

The important thing is to use Class I ceramic COG/NPO dielectric types.

 

[kumiroff]

So what is better here? FKP2 or ceramics? ))

 

[HalFoster]

Ceramic. C0G

 

[rayma]

Are C0G's even available in disk?

Yes, have been for many years, long before smt became common.

 

[HalFoster]

Thank you! I never realized that - I just always wound up with something in a MLCC or mica by default I guess...

 

[kumiroff]

Are these OK?

 

[rayma]

Just make sure the mfr spec sheet does say COG/NPO dielectric.
If it doesn't, it probably isn't. There are big differences in the types.

https://www.kemet.com/en/us/technical-resources/heres-what-makes-mlcc-dielectrics-different.html

 

[rayma]

Are these OK?

If you choose a type 5C or 5G dielectric.
See the link in the previous post.

 

[kumiroff]

Understood. Thank you all!

 

[Bonsai]

Yes, for many years, long before smt became common.

They still are. See below. On Mouser select capacitors>MLCC>Through hole > radial > COG. There are dozens of values in 2.5mm pin spacing and 5/5.08 pin spacing.

Personally, I would not use film for amplifier compensation given the superb NP0/COG capacitors available now at high voltages.

 

[rayma]

Yes, this type of package is for the "those smt are too darn small" builder.
Just keep the leads short, and buy them with straight leads, not crimped, for lowest inductance.

 

[kumiroff]

Thanks, I found muRATA capacitors in a local store.

 

[EUVL]

Personally, I would not use film for amplifier compensation

I would.
Ask Viktor (what he uses in his -155dB oscillators).


Patrick

PS. I have seen his measurements.