XAUI Driver Spec
Hello all,
Last week in Austin the XAUI group decided to change Max Diff. Amplitude to
1.6 volts. As I understood it, the rationale for increasing the max amplitude
was to achieve commonality with the Infiniband spec. Although I agree with
the spirit of this rationale, I checked the Infiniband spec and found
that they are trying to drive a cable as well as a backplane with one
electrical specification; thus the reason for the 1.6v spec. In this
case, I'm not sure if it is worth matching the Infiniband spec in this
one area. My feeling is that a driver circuit can be made to drive
up to either 1.0 volt or 1.6 volt relatively easily; but it would be
much more troublesome for a (XAUI) receiver to tolerate 1.6 volts
*needlessley*.
So, if the above reasoning is agreed to by others, I would propose that we
stay with 1.0 volt max. diff. amplitude that is in the current draft 1.0
(page 119, line 22).
-Robbie Shergill
National Semiconductor