How to do PCB trace characteristic impedance correctly?

[grahamUTKMN]

Hi,

In the past I've asked the board manufacturer to adjust certain traces to get the correct impedance characteristic, but is there a correct way to do it in Eagle?

Thanks,

G

[m.neujahr_at_moe]

Hello @grahamUTKMN,

in Eagle you can do it by defining "Netclasses":

First define the desired wire-width depending on your layer-stack.

Then you have to change the net-class of the net to the new net-class (right-click on net -> properties) and after that you can route the trace

[grahamUTKMN]

But how does that calculate the impedance?

G

[m.neujahr_at_moe]

Hello @grahamUTKMN,

the calculation has to be done by your own:

• PCB-Way online calculator 
• Omnicalulator 
• EEWeb calculator 
• https://www.google.com/search?client=firefox-b-d&q=pcb+impedance+calculator+online 

[jorge_garcia]

Just to add to what @m.neujahr_at_moe mentioned.

I've used the saturn pcb toolkit (google it) to do these types of impedance calculations.

Let me know if there's anything else I can do for you.

Best Regards,