RE: Required data in IBIS Models (was Re: Clarification needed.)

Vmeas is used by the simulator to determin the delay of the output stage
driving the manufacturer's reference load to the measurement voltage
(Vmeas). The prop delay of the part is specified into this load also. The
simulator is trying to do a timing analysis, time of flight, which includes
the time of the driver and the time of the trace on the board. This
information is used when analyzing total delays so that overall system
timing can be verified.

Tom Dagostino
Modeling Manager
Mentor Graphics Corp.
SAE
tom_dagostino@mentor.com
503-685-1613

-----Original Message-----
From: Adam.Tambone@fairchildsemi.com
[mailto:Adam.Tambone@fairchildsemi.com]
Sent: Thursday, May 24, 2001 7:55 AM
To: Phani Putrevu
Cc: ibis@eda.org; ibis-users@eda.org
Subject: Re: Required data in IBIS Models (was Re: Clarification
needed.)

Phani, I am just beginning to use IBIS models in XTK, so I am not entirely
aware of how the Vmeas parameter is used. I do know that it is used for
timing analysis and that IBIS2XTK will complain if it is not there. I
mentioned that he 'wanted' the parameter because I have received more than
a few complaints from customers when I did not include it in a IBIS
datasheet ( my apologies to anyone who has encountered this ). I have
since reviewed all IBIS datasheets I have generated and revised them to
include this parameter if it was not included originally.

I would like to hear more about how this parameter is used.

Adam Tambone

Phani Putrevu <pputrevu@lucent.com> on 05/24/2001 10:27:15 AM

To: Adam Tambone/SouthPortland/Fairchild@Fairchild
cc: ibis@eda.org, ibis-users@eda.org

Subject: Required data in IBIS Models (was Re: Clarification needed.)

The IBIS spec states that the model subparameter Vmeas is optional. The
ibis
checker does not complain if this is not present. HSpice can read an IBIS
file
even if the Vmeas is not specified. But I believe some tools (ICX) require
this parameter to be present. (I do not use IBIS models - I was only
involved
in developing the models.)

Does it mean that the tool is not compliant. What additional information is
derived from this parameter? Should a tool rely on this information to
produce
an output, or should it produce the 'approximate' output that the vendor
specified in the IBIS model.

regards,
Phani

Adam.Tambone@fairchildsemi.com wrote:
>
> Anbazhagan,
>
> oops... forgot to mention that you also want Vmeas.
>
> Adam

 
Received on Thu May 24 09:20:55 2001