topic Re: How to do PCB trace characteristic impedance correctly? in EAGLE Forum

How to do PCB trace characteristic impedance correctly?

grahamUTKMN — Tue, 07 Jun 2022 11:39:10 GMT

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,

Betreff: How to do PCB trace characteristic impedance correctly?

m.neujahr_at_moe — Tue, 07 Jun 2022 13:47:06 GMT

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

Betreff: How to do PCB trace characteristic impedance correctly?

grahamUTKMN — Tue, 07 Jun 2022 16:10:05 GMT

But how does that calculate the impedance?

Betreff: How to do PCB trace characteristic impedance correctly?

m.neujahr_at_moe — Wed, 08 Jun 2022 04:24:56 GMT

Hello @grahamUTKMN,

the calculation has to be done by your own:

Re: How to do PCB trace characteristic impedance correctly?

jorge_garcia — Wed, 08 Jun 2022 20:20:08 GMT

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,