Re: [IBIS-Users] what is the use of minimum and maximum data in IBIS?

> Hi,guys. Usually in IBIS simulation, we use typ data, then what's the use of
> min. and max. data?

I am not a big IBIS model user, nor a big fan of IBIS, though I've
been following IBIS since its earliest days. However, if an IBIS
model contains meaningful Min/Typ/Max data, then I would rarely use
the Typ data and instead mostly use the Min and Max data. That's
because I'm looking for best and worst case results. Simulations with
a typical model are nice to look at, but they don't show me critical
data that I need (from a timing or signal integrity viewpoint).

> Some papers said," a slow model can be created by combining the min.
> currents with max. ramp time and max. package element values. The slow model
> can be used to determine the propagation time". However, in my
> understanding, IBIS model can only simulate the buffer delay time. Is it
> true that it can be used to determine the propagation time in that way?

You can never obtain buffer delay time from an IBIS model. IBIS
models do not represent the whole buffer. They represent only how the
buffer interacts with the external circuit, and can be used to
simulate how the buffer drives into (or receives from) other devices
and interconnects (traces or wires). The delay through the buffer is
NOT represented by nor included in its IBIS model.

I use IBIS model simulations to derive waveforms on the interconnect
or at the receiver, and propagation delays of those signals on the
interconnect. I use the corner models for that.

It is not always the case that the slowest buffer results in the
longest interconnect propagation time; nor that the fastest buffer
results in the minimum interconnect delay. I am one who likes to
simulate all corners and see for myself which ones are minimum and
maximum.

Andy

-- 
This message has been scanned for viruses and
dangerous content by MailScanner, and is
believed to be clean.
--------------------------------------------------------------------
|For help or to subscribe/unsubscribe, e-mail majordomo@eda-stds.org
|with the appropriate command message(s) in the body:
|
|  help
|  subscribe   ibis       <optional e-mail address, if different>
|  subscribe   ibis-users <optional e-mail address, if different>
|  unsubscribe ibis       <optional e-mail address, if different>
|  unsubscribe ibis-users <optional e-mail address, if different>
|
|or e-mail a request to ibis-request@eda-stds.org.
|
|IBIS reflector archives exist under:
|
|  http://www.eda-stds.org/pub/ibis/email_archive/ Recent
|  http://www.eda-stds.org/pub/ibis/users_archive/ Recent
|  http://www.eda-stds.org/pub/ibis/email/         E-mail since 1993