Re: [IBIS] DC and AC data mismatch error in IBIS


Subject: Re: [IBIS] DC and AC data mismatch error in IBIS
From: Al Davis (aldavis@ieee.org)
Date: Mon Oct 21 2002 - 18:10:32 PDT


On Monday 21 October 2002 04:46 pm, Tom Dagostino wrote:
> I change first point in the pulldown max from -2.22838e+00 to
> 2.2838e+00 and the errors went away. This removed a
> non-monotonic issue in the curve. It looks like a bug in the
> older version. The load line should be intersecting the
> pulldown curve in the active region, not in the clamp region.
> The -6.58V message is the part that concerned me.

It looks like a bug in the new version to me. It has negative
resistance in the last step. Some simulators will extrapolate
that resulting in another zero crossing. That -6.58 message is
in the extrapolated region.

So, Moshiul, yes it is something to worry about. The 3.2.8
parser is ok. The 3.2.9 parser has a serious bug in that it
failed to report the error.

But, as Tom said, simply tweeking that data point is enough.

Actually, your file has too many data points.

Check the derivative! The file has some problems that are very
clear when you look at the derivatives, and will probably slip
by otherwise.

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