Re: IBIS BIRD67 - Increase V-T Table 100 Point Limit

Bob:

We will introduce BIRD67 and discuss it at the Meeting on Friday,
October 27,2000.

Your points will be discussed at that time. They are valid based
on the fact that the original limits were never expected to
compromise model accuracy.

Another point expressed privately will also be raised. It is whether
the limit should be 1001 to allow "nice" begining and end points
on V-T tables along with "nice" spacing values. For example, 1001
table entries spanning 0nS to 10.00nS with 10pS spacing.

Bob Ross
Mentor Graphics

"Haller, Robert" wrote:
>
> Bob R. and Ian,
> Nice to see this bird, but I have a question/issue.
> I agree that 100 point V-T curve limit is often insufficient because of
> increased accuracy requirements. I believe the bird falls short (IMHO) by
> not relaxing the 100 point limit in the I-V curves also.
>
> The same argument you give for increasing the number of points in the V-T
> curves also exist for I-V curves. In the past, I discussed this issue with
> other model creators, and they too have run into cases where they could not
> accurately include all of the "I" points needed for min typ max because
> of the common "V" axis. One example is when I created then correlated models
>
> for HSTL devices designed with on chip parallel termination. Very small
> changes in I result in significant changes in V. If you don't nail the exact
>
> operating points with enough I-V points you obtain DC offsets in your
> resultant output waveforms.
>
> I would strongly suggest while modifying 100 -> 1000 point change to the V-T
>
> curves we should also relax that restriction on the I-V from 100->1000.
> We should be proactive, If additional points are not required they don't
> have
> to be used, but if more points are needed the limitation is not in the
> specification.
>
> regards,
> Bob H.
>
> Cereva Networks
> 3 Network Drive
> Marlboro MA. 01752
> Phone: 508-486-9660 X 3365
> FAX: 508-486-9661
> Email: rhaller@cereva.com
>
 
Received on Thu Oct 26 09:31:28 2000