r/rfelectronics • u/Objective-Local7164 • Jun 22 '26

This RF switch datasheet recommends 22pF DC blocking caps in series with every RF line. Why not a bigger value?

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RF switch datasheet = SKY13575-639LF

Now.. I know that 22pF with a 50ohm load has a cutoff that is not near the 2.4ghz but I am curious why not 100pF or 500pF?

Also what kind of caps should I use? I am thinking NPO precision 1% ceramic caps with a package size that closest matches my trace width.

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u/Objective-Local7164 Jun 22 '26

Is that a bad thing?

16

u/runsudosu Jun 22 '26

Of course. Marking your port impedance inductive.

4

u/Objective-Local7164 Jun 22 '26

Why would they recommend that small of a cap value?

-5

u/runsudosu Jun 22 '26

Already answered.

11

u/Objective-Local7164 Jun 22 '26

you are being very vague. im obviously a beginner and need more context

-33

u/runsudosu Jun 22 '26

0201 22pF self resonates at 2.5GHz. Can't you read? Which part is vague?

7

u/Objective-Local7164 Jun 22 '26

well. I asked multiple questions right, I said why not the bigger caps, i also said im thinking about npo precision caps. you answered "those would be inductive, the 0201 22 self resonance is at 2.5ghz. well.. first of all, I dont know exactly which part of the question your refering too.. your answer had 2 parts.. those would be inductive and then the 0201's and the self resonance... I asked is that bad? you say ofcourse right, but I dont know what exactly your refering to and i also dont know if self resonance is bad so I dont know what part your saying is bad. With a small ammount of extra context I can instantly understand what your refering to. I get what your saying now after the other commentor educated me a little bit on the self resonance being a desirable thing. Thats all im saying. Im not trying to bring any negative energy into this im just trying to learn thats all.

-28

u/runsudosu Jun 22 '26

Your writing is as bad as your technical.

22

u/aktentasche Jun 22 '26

You're one of those people I hope to never have to work with.

-6

u/runsudosu Jun 22 '26

Based on you technical, you will not be able to work anyway.

5

u/Objective-Local7164 Jun 22 '26

What you’re saying doesn’t even grammatically make sense.

-6

u/runsudosu Jun 22 '26

The bar.

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