Hello,
I am working on a 4 layers PCB board with some controlled impedance tracks.
I have a doubt on the stackup I should use because I don’t see the same things on the stackup picture on the page below and the prepeg datasheet : different top/bottom copper thickness and permittivity are different. Moreover, whatever is the value, I’m not able to find out how the 50 Ohm track width has been calculated.
And finally, the Kicad rule file seems to says another version for top/bottom thickness (35µm).
| Kicad | Picture | Datasheet | |
|---|---|---|---|
| permittivity | 4.3 | 4.3 | 4.7 |
| Copper top/bot | 35um | 40um ? 18um ? | - |
| Loss tangent | 0 | 0 | 0.011 |
I’m definitely lost.
Can you help me ? Thank you
4 Layer 1.6mm ENIG Design Rules - 
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