Subject: Re: About WARNING of ibischk2

From: Paul Gregory <[email-masked]>
Date: Mon, 06 Apr 1998 15:02:37 MDT

>What I would like to know is since this is a WARNING and not an
>ERROR, how concerned does the model developer need to be ??

>Regards,
>Syed
>National Semiconductor Corp. 

I think that the concern is more with the model consumer, not
the developer.  Any time I get a model that does not pass the
ibischk utility, my confidence in the model goes down.  I 
usually notify the model supplier that the model had some
warnings and ask for clarification as to why it does not 
pass.  Then I spend time examining the model in closer detail 
to try to understand the warnings/errors. While this is a good 
thing from the point of view that I become more knowledgeable about
the model, it is not a desired thing.  I need to have confidence 
that the models are accurate, and passing the ibischk utility
is the first step.

 -- Paul Gregory

   phone: (208) 396-5086               USmail: Hewlett-Packard
     fax: (208) 396-4122                       M/S 143
   email: [email-masked]                  11311 Chinden Blvd.
                                               Boise, ID  83714

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From: [email-masked] (Syed Huq)
Date: Mon, 6 Apr 1998 14:38:27 -0700

Chris/Matthew:

Thanks for your comments. I would like to know the exact % delta between
the V/I and V/T and not just 'not within 2%'. This will really tell me
if I should be alarmed..Also, it would be nice to know
if a certain greater than 'x'% deviation can cause problems with simulators.

If a 5% difference causes uVolt variation on simulation, then this
WARNING is never a serious thing and it can always be ignored.

Regards,
Syed.

> From [email-masked] Mon Apr  6 11:34:43 1998
> Sender: [email-masked]
> Date: Mon, 06 Apr 1998 11:25:37 -0700
> From: Chris Rokusek <[email-masked]>
> Organization: Quad Design Technology
> X-Mailer: Mozilla 3.01 (X11; I; SunOS 4.1.4 sun4m)
> To: Syed Huq <[email-masked]>
> Cc: [email-masked]
> Subject: Re: About WARNING of ibischk2
> Content-Type> : > text/plain> ; > charset=us-ascii> 
> Content-Transfer-Encoding: 7bit
> 
> Hi,
> 
> Perhaps the ability to set the % used in the check should be allowed.  I
> recall that we discussed this before...
> 
> Or, perhaps the 2% should be increased to 5%.  What percentage would
> allow these measured models to pass with some headroom? 
> 
> Chris
>

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From: [email-masked] (Syed Huq)
Date: Mon, 6 Apr 1998 15:29:09 -0700

Paul,

A model can pass the parser and still get WARNINGS. That does
not mean that the model is **Bad**. We have devices whose V/I
characterisitcs are non-monotonic. So, the parser will ALWAYS
give you WARNINGS. I do agree that understanding the WARNINGS
is a good thing to do.

..and if the model never passes the parser...throw it away.

Regards,
Syed

> From [email-masked] Mon Apr  6 15:05:50 1998
> From: Paul Gregory <[email-masked]>
> To: [email-masked]
> Date: Mon, 06 Apr 1998 15:02:37 MDT
> Reply-to: [email-masked]
> X-Mailer: Elm [revision: 212.4]
>

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From: Paul Gregory <[email-masked]>
Date: Mon, 06 Apr 1998 17:32:57 MDT

>National Semiconductor Corp.

I never suggested that a model that has warnings/errors is
bad. Only that such models require more study to understand
the reasons for the warnings/errors.  And this is, in my
opinion, "not a desired thing".  It is at worst, an issue of
model accuracy and at best, an issue of model confidence.

 -- Paul Gregory