RE: Non Monatomic waveform, practically, how important?

Also, don't forget that some of these non-monotonic curves come from the
numerical separation of the pulldown/up and clamp curves which will
become monotonic again after they are added back together. The problem
is that the checker checks for non-monotonocity without adding them up.

Arpad
=======================================================================

The classic reason we argued against allowing non-monotonic IV curves
was because the non-monotonic behavior requires a feedback path (and
thus a delay) that we have never been able to properly define. If you
don't know the feedback path delay then you do not know the inherent
non-stable point for the driver. We have tried to work with IC companies
that have this problem (and I think we did get a few non-real examples
from some people) but the actual resolution of the feedback delay has
never been completely addressed.

I think that the current IBIS simulators take one of two approaches:
1) Allow the non-monotonic behavior and assume 0 delay.
2) Filter out the non-monotonic behavior automatically.

Which one is right? Depends on the driver and the feedback delay.

regards,
Jon Powell
Manager, High Speed Consulting Services, Viewlogic Systems.
Received on Tue Nov 10 09:42:31 1998