About xSignals

[mulfycrowh]

Hi everyone,

I would like to route as differential the paths TX_N, TX_P, RX_N and RX_P as shown on the attached screenshot.
U14 could be defined as the source, the connector (P2) as the destination.
As you can state, there are 4 series resistors.
I went to Design > xSignals > Create xSignals.
How should I proceed?
I tried many things.
Could you help please?

[mulfycrowh]

If I select P2 as source and R48, R50, R52, R54 as destinations in the wizard, AD detects all 4 differential signals.
But if I select P2 and U14, AD detects nothing.

[goncaloc]

The signals coming from U14 are not defined as differential signals, they should, as it is done on both TX and RX, end with _P and _N

[robertferanec]

goncaloc nice spot! mulfycrowh is it working after naming the nets correctly?

[mulfycrowh]

robertferanec I thought that AD could automatically detect the series resistor within the differential pair. It is doable!

[mulfycrowh]

If I introduce another differential pair net, it is OK.

[mulfycrowh]

Now. I found that the suggested differential routing is not good as shown on the attached screenshot.
It is like like an automated routing.
Is there a way to go, in that case from the connector to the diode directly?

[przemek]

Hi,
you can adjust your traces after routing by sliding them. By the way, maybe rotate D9 by 180° to keep the nets close each other for as long as possible?

[mulfycrowh]

Here is the result of my differential routing.
It is very hard to keep the impedance on each point because of the size of the components.

[goncaloc]

Looking good

[mulfycrowh]

goncaloc What is the short key to disable snapping when routing differential pairs?
Thanks.

[przemek]

It should be Shift + E - switching between snaping to all layers/current layer/snapping off.

[robertferanec]

When routing, hold down CTRL