[IBIS-Users] RE: an equivalent load applied to the model's I-V tables yields different voltages.

Hi,

 

I am trying to make a model for a pseudo LVDS pad, but I can't extract
the proper IV tables from it.

To extract the rise/fall waveforms I have to run the simulation at high
frequency for a while (250ns) - before it gets to the proper voltage
levels.

But it looks like the IV curves yield different voltages. 

These errors are coming from my Hyperlynx session:

 

 

ERROR - Model LVDSTX: The [Rising Waveform] 

      with [R_fixture]=50 Ohms and [V_fixture]=0V

      has TYP column DC endpoints of  0.01V and  0.38v, but

      an equivalent load applied to the model's I-V tables yields

      different voltages ( 1.17V and  1.19V),

      a difference of 6615.72% and 4640.59%, respectively.

ERROR - Model LVDSTX: The [Rising Waveform] 

      with [R_fixture]=50 Ohms and [V_fixture]=1.29V

      has TYP column DC endpoints of  0.78V and  1.64v, but

      an equivalent load applied to the model's I-V tables yields

      different voltages ( 1.37V and  1.33V),

      a difference of 1712.86% and 916.29%, respectively.

 

 

Has anyone seen such an Error & has an Idea on how should I extract the
IV tables correctly?

I made some simple IBIS models before - but I can't make one for this
pad. I am not an expert in IBIS & any help is appreciated.

 

Thanks 

Marek


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