RE: new ibischk3 V3.2.6

Bob,
I'm not sure I agree with your statement that a model with end point I-V
currents that are "extremely large (such as 1e20)" "might actually be
correct" even if those data points are produced from a valid spice deck.
The purpose of a model is to reflect reality where possible and 1e20
amps????

Aubrey Sparkman
Signal Integrity
Aubrey_Sparkman@Dell.com
(512) 723-3592

> -----Original Message-----
> From: Bob Ross [mailto:bob_ross@mentorg.com]
> Sent: Tuesday, January 09, 2001 7:26 PM
> To: Syed Huq
> Cc: ibis-users@eda.org
> Subject: Re: new ibischk3 V3.2.6
>
>
> Syed:
>
> The new ibischk3 changed the Warning message to an Error
> message when the mismatch exceeded 10%. In your example,
> the mismatch between 0.41 and -0.71 exceeds the 10% value
> of the range (.21v). There may exist a real problem that
> needs to be examined. This change is documented as BUG47:
>
> http://www.eda.org/pub/ibis/bugs/ibischk/bug47
>
> However, the -0.71 value is suspicious. I have seen a
> similar problem when some of the end point I-V currents are
> extremely large (such as 1e20) and cause ibischk3 to
> not properly converge to the correct DC endpoints. You
> might check this and try smaller values if such large
> values exist. Your model might actually be correct.
>
> Bob Ross
> Mentor Graphics
>
>
> Syed Huq wrote:
> >
> > I ran a model with the NEW ibischk3 ver3.2.6 and get this:
> >
> > new version:
> > ERROR - Model XYZ_IO: The [Rising Waveform]
> > with [R_fixture]=50 Ohms and [V_fixture]=2.5V
> > has TYP column DC endpoints of 0.41V and 2.50v, but
> > an equivalent load applied to the model's I-V tables yields
> > different voltages (-0.70V and 2.50V),
> >
> > In the earlier version(V3.2.5),this would show up as a
> WARNING. Since now
> > it shows up as ERROR, the file fails.
> >
> > old version:
> > WARNING - Model 'XYZ_IO': TYP AC Rising Endpoints ( 0.41V,
> 2.50V) not within
> > 0.042V (2%) of (-0.70V, 2.50V) on VI curves for
> 50 Ohms to 2.5V
> >
> > Why was this changed to ERROR ?
> >
> > Syed
>