Re: help with ibischk3 warnings and min data

Betty,

Although I haven't gone through the math to get exact numbers,
I see that your VI curves do not fall to zero current at zero volts
(almost 10mA on the pullup). So there will be a DC offset.

Mike LaBonte
Cadence Designs Systems

Betty Luk wrote:
>
> Hi,
>
> Actually, I noticed something strange about the warnings generated from the
> IBIS golden parser. I've pasted all the warnings below:
>
> WARNING - Model 'tristate_driver': MIN AC Rising Endpoints ( 0.00V, 0.89V)
> not within
> 0.018V (2%) of (-0.02V, 0.84V) on VI curves for 50 Ohms to 0V
> WARNING - Model 'tristate_driver': MIN AC Rising Endpoints ( 1.84V, 3.00V)
> not within
> 0.023V (2%) of ( 1.83V, 2.85V) on VI curves for 50 Ohms to 3V
> WARNING - Model 'tristate_driver': MIN AC Falling Endpoints ( 0.00V, 0.89V)
> not within
> 0.018V (2%) of (-0.02V, 0.84V) on VI curves for 50 Ohms to 0V
> WARNING - Model 'tristate_driver': MIN AC Falling Endpoints ( 1.84V, 3.00V)
> not within
> 0.023V (2%) of ( 1.83V, 2.85V) on VI curves for 50 Ohms to 3V
> WARNING - Model 'tristate_driver': MAX AC Rising Endpoints ( 0.00V, 1.89V)
> not within
> 0.038V (2%) of ( 0.00V, 1.98V) on VI curves for 50 Ohms to 0V
> WARNING - Model 'tristate_driver': MAX AC Rising Endpoints ( 1.34V, 3.60V)
> not within
> 0.045V (2%) of ( 1.34V, 3.79V) on VI curves for 50 Ohms to 3.6V
> WARNING - Model 'tristate_driver': MAX AC Falling Endpoints ( 0.00V, 1.89V)
> not within
> 0.038V (2%) of ( 0.00V, 1.98V) on VI curves for 50 Ohms to 0V
> WARNING - Model 'tristate_driver': MAX AC Falling Endpoints ( 1.34V, 3.60V)
> not within
> 0.045V (2%) of ( 1.34V, 3.79V) on VI curves for 50 Ohms to 3.6V
>
> For example, in the last warning statement, it states the correct range to
> be ( 1.34V, 3.79V). If my supply voltage is 3.6V, how can the final
> voltage be 3.79V, higher than 3.6V?
>
> Thanks very much,
> Betty
>
...
 
Received on Tue Nov 21 15:43:10 2000