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JohnsonMiller , 08-27-2023, 06:01 AM

For the characteristic impedance of a transmission line, either single-ended or differential, we set a reference plane. Can we assign a DC voltage to that reference plane and assume DC as GND in a small signal? or not that plane should be 0V or GND all the time?
In other words, in multi-layer PCB can we use a reference plane for distributing power, say 1V, and it still acts as a reference plane?
I checked this question with simulation tools, but do not know how to model and simulate it.

qdrives , 08-27-2023, 03:11 PM

There are so many video's on this topic, most known are the ones from/with Eric Bogatin. This video https://www.youtube.com/watch?v=icRzEZF3eZo comes to mind.

Anyhow, the return plane is the plane that carries the return current back to the driver. If it is a 'power' plane, how does the current get back to driver?
The best way then is to place a capacitor close to the driver that connects the power plane to the Gnd of the driver.

What (kind of) simulation tool are you using?

JohnsonMiller , 08-28-2023, 02:05 PM

Thank you, I checked the referred video and got my answer.

I was trying to check it with HyperLynx, which seems not good for this task.

qdrives , 08-28-2023, 03:16 PM

I am no expert in HyperLynx (read: never used it, nor any other SI tool), but I would have expected that it should be able to do so...
Glad you got your answer.