Monotonicity

Hello all,

I believe there were many discussions on monotonicity before
I joined the IBIS mailing lists. Perhaps someone would be kind
enough to help me with this issue.

We are currently trying to encourage a semiconductor supplier
to provide us with IBIS data for a set of components. Their response
is lukewarm. An argument used is that because the buffers have
non-monotonic curves, IBIS models cannot be created.

On reading IBIS 2.1, this appears to be true. An example of an
output curve is a follows:

   
                 | *
            Vdd +
                 | * Pulldown
                 |
                 | *
   Vout |
                 | *
                 | *
          0.5Vdd + *
                 | *
                 | *
                 | *
                 | *
                 | *
                 | *
                 | *
                --------------------------------------------------
                                 Iout

Has anybody else had to deal with this issue?

Why is their a restriction put on monotonicity? Is it because
some simulators cannot handle this case?

In 2.1 it states that most simulators filter non-monotonic data.
Does this mean that it's OK to feed non-monotonic IBIS models to
most simulators i.e. it will generate results based on filtered
data?

I've looked at the FAQ, but this seems to say that the only reason for
non-monotonic behaviour is due to the way clamping and active
curves are generated!

Any feedback appreciated,

Regards,
John

-- 
John Fitzpatrick   <John.Fitzpatrick@ln.cit.alcatel.fr>    
Alcatel CIT, 4 rue de Broglie, 22304 Lannion, France
Tel: (+33)96.04.79.33  Fax: (+33)96.04.85.09