Using impedance on PCB design

Hi everyone, I am trying to make PCB. I did it once with pin headers, now I want to make real PCB with chip's. RP2040 and Wiznett5500. I couldn't find Wiznett5500's impedance HH-1M1608-121JT . I found MH2029-300Y which is used by Sparkfun. Screen Shot 2021-10-22 at 08.33.27 Can I use this ? They re not looking the same (I am beginner, I am probably wrong :slight_smile: )
Screen Shot 2021-10-22 at 08.35.51

RP2040 has AGND and ADC_VREF pin, should I use these for Wiznett ? They connected AGND to GND so should I do the same or should I use rp2040's AGND.
Screen Shot 2021-10-22 at 08.38.33

Which datasheet could you not find ?
this one
or this one ?

My question is wrong I will edit it. I found datasheet's but I couldn't find components in my country . I couldn't find HH-1M1608-121JT this on my country. Can I use Sparkfun's MH2029-300Y impedance( used by Sparkfun)?
I saw another problem too. Wiznett w5500's crystal. No-one selling 25MHz KX-7_NM ( what sparkfun is using) . I don't know what wiznett is using . I only know it is 25Mhz and they are using 18pF capacitors. I tried to calculate but I don't know w5500's oscillator transconductance. I found this but I don't know if it works crystal , crystal2 .

Maybe because you're searching for an "impedance" instead of an "inductor"? Are no inductance values listed for L3 and L12? There are probably thousands of parts that would fit there, all with different part numbers and from different manufacturers, as something like that is a commodity part.

HH-1M1608-121JT I am finding this but not in my country. I am not finding original supply so I am looking for alternatives. In my country I found MH2029-300Y (which is Sparkfun using), can I use this instead of original one? I shared the values. I am a beginner I shared this because they use different values. I want to be sure before use MH2029-300Y. If Sparkfun use this inductor, there must be something.

Those look like extended parameters, not the basic inductance in Henries, milliHenries, or microHenries... the impedance at 100MHz is a limiting parameter, AFAIK, not the basic parameter, inductance.

You should be looking for a part with the same inductance and PCB footprint. After that, compare impedance at 100MHz and all that...

I will use 0805 footprint. If MH2029-300Y won't work, I have to order HH-1M1608-121JT from aliexpress then. Okay , thank you.

Well, you seem to know what you need. I'm used to being ignored. Good luck.

@aarg, I didn't understand you. I didn't ignore you. I wrote what I understand , sorry. You said

You should be looking for a part with the same inductance and PCB footprint.

Did you say this about HH-1M1608-121JT ? So you are saying I need to use original supply.

Did you read what I posted?

The exact opposite. I'm saying you are obsessing over part numbers. There are literally hundreds or thousands of parts that will work there. It's just an inductor... a plain, ordinary, common, inductor!

Hmm, okay . Thank you for your help. Sorry for taking time.

Try to learn the inductance value from the BOM and/or schematics of the device you're copying.

I just have the name, I am looking only schematic.

Then you need to look up the part specifications, the inductance will be prominently featured there. Can you supply a clickable link to the part?

HH-1M1608-121JT 120 ohm. MH2029-300Y 30 ohm. Is that means I need to find 120ohm ?

Oh, I see, the method of specification is by |Z|... yes, find another source and start comparing those figures... but again, you do not need to match the exact part number, just the specs...

By the way, depending on your custom PCB layout, the optimum value for those might be different.

These are ferrite beads. They are not plain inductors, and act more like frequency-dependent resistances, due to the lossy nature of ferrite in the 100MHz region.
The impedance at 100MHz is pretty much the key spec here.

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MarkT, thank you. I will use MH2029-300Y because when I resarch WIZArduino they use 30ohm too. Can I ask you another question?
Here is my question:
I saw another problem too. Wiznett w5500's crystal. No-one selling 25MHz KX-7_NM ( what sparkfun is using) . I don't know what wiznett is using . I only know it is 25Mhz and they are using 18pF capacitors. I tried to calculate but I don't know w5500's oscillator transconductance. I found this but I don't know if it works crystal , crystal2 .

For crystals its the pin capacitance that matters - for instance two 18pF caps act as 9pF (as they are in series from the crystal's perspective), and then you add the extra capacitance of the chips pins. For instance if the pins are 10pF, thats 28pF total at each end of crystal, so it sees 14pF.
The values are not very critical so most crystals will oscillate, but the rated frequency specs rely on the capacitance being right (more important for a high accuracy crystal, not an issue for ethernet).