The termination wizard shows the driver output impedance is 49.6 ohms. The effective impedance seen by the driver (looking toward the receiver) is 106.6 ohms. 106.6 ohms - 49.6 ohms = 57 ohms. That is what the termination wizard is suggesting. I hope that helps you out.
Ed, the driver output impedance is not 49.6 ohms.
If it were 49.6 ohms then I should get 0.9V if a 50 ohm load is put at the output of the buffer. No tx line, just a 50 ohm load (voltage divider).
But I get about 0.45V when I put a 50 ohm load. See attached.
So driver impedance is 150 ohms.
Why can't the wizard figure it out.
hyp2.png 65.1 KB
I am going through exactly the same problem. I also calculated the output impedance of the driver in the same way as you did. It doesn't match with the termination wizard.
Were you able to solve this issue?