I was looking at AIRD-03-221K inductor (a second datasheet here), and noticed it does not mention its self-resonant frequency (SRF).

Of course, it mentions the frequency they tested it at, its 100Khz, so It can "handle" at least 100Khz before it starts losing inductance. (Screenshot from first datasheet):

frequency measure inductor

Is it possible to tell its maximum self-resonant frequency (even with an approximation) just by the datasheet's rest data, before ordering it? (I know I can test it myself in the lab after I order it, but I would like to know beforehand).

Screenshots from first datasheet:



  1. I want to use the inductor on a buck converter which runs at 1Mhz, driving a 1.5A load. Might be helpful information.

  2. For some inductors that the datasheet actually tells you the Self resonant frequency, I noticed the more the inductance increases, the more the SRF drops. maybe this can help somehow?:



1 Answer 1


My personal rule: never buy an inductor that doesn't specify SRF unless of course you clearly are going to be running nowhere near it but, how do you know if it ain't specified? Hence, I always buy inductors from suppliers that specify SRF irrespective of the application because, it tells me that the supplier (or manufacturer) knows what they are doing.

I guess there'll be some exceptions to my "quality" rule but, I don't recall ever having gone against this other than when a chip supplier recommends such and such an inductor in their data sheet to use with their chip and that inductor doesn't have an SRF specified in its data sheet. I'm thinking here of switch-mode power supply chips such as boost or buck converters.

  • \$\begingroup\$ Yet this inductor series is from one of Europe's biggest electronics suppliers, but doesn't seem to mention the SRF. Surely RS knows what it's doing, so how can I use these please? \$\endgroup\$
    – Paul Uszak
    Commented Oct 10, 2022 at 20:46
  • \$\begingroup\$ If SRF is important in your application and you can't find an answer from RS PRO then you have to dig deeper. I never use an inductor that either doesn't state the SRF or, I'm unable to estimate it from dimensions. More specifically, I want to see SRF in data sheets if I'm pushed @PaulUszak \$\endgroup\$
    – Andy aka
    Commented Oct 10, 2022 at 22:04

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