Re: [IBIS-Users] rising waveform

Hl YY Lau:

I would like to see the exact end points of the Rising Waveform
Max table because there is a numerical issue.

The Warning Message should be issued only if the mismatch is
equal to or greater than 2.0% of the total calculated swing.
In this case the swing is from 1.71 to 3.10 V or 1.39, and
2% of this is 0.0278 V.  Your actual mismatch 0.03 V - outside
of the 2% tolerance.  Howover the reported mismatch is 1.91%,
and no Warning should have been issued.

So your starting point might be rounded up to 1.74 from a
smaller value - causing a Warning message, but the actual
values used to calculate the persentages might be the unrounded
values - inside the 2% tolerance.

If this is the case, we are not doing the calculations
and reporting correctly

However, there could be other numerical issues.  I would have
to see the full model to determine this.

Bob

lau yy wrote:
> Dear ALL,
>  
> Can someone show me my mistake? The warning message like below.
>  
> WARNING - Model DQ0: The [Rising Waveform]
>       with [R_fixture]=70 Ohms and [V_fixture_max]=3.1V
>       has MAX column DC endpoints of  1.74V and  3.10v, but
>       an equivalent load applied to the model's I-V tables yields
>       different voltages ( 1.71V and  3.10V),
>       a difference of  1.94% and  0.01%, respectively.
> Thanks alot.
>  
>  
>  
> rdgs
> yylau
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-- 
Bob Ross
Teraspeed Consulting Group LLC     Teraspeed Labs
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