Re: About ibischk2+

Hello Nakajima-san:

    My answers are below. I hope this helps.

               Best Regards,
               Stephen Peters
               Intel Corp.

> Dear All,
>
> I checked IBIS models by ibischk2+.
> I have two questions.
> Could you support me ?
>
> 1) Dose ibischk2+ make errors when IV table is non-monotonic?

      The ibischk2+ program checks for non-monotonic data because many
simulators
      will not accept non-monotonic I/V data. Please note however these are
warnings,
      not errors. Also be aware that the non-monotonic data may be in the
result of
      subtracting the power/gnd clamp current from the pullup and pulldown
currents,
      and that once the two curves are summed together (as the simulator will
do) the
      data may be monotonic.

      I notice that there are also warning that indicate that the V/T curves
in your
      model do not settle to within 2% of the final DC value predicted by the
I/V
      curves. This may require some investigation.

> 2) Why dose not ibischk2+ use "R_dut" value?

      The R_dut value represents part of the test load used when extracting the
      V/T curves. It is included to document the test/extraction conditions.

>
> ---- Example of "1)" ---------------------------------------------------------
> WARNING (line 47) - Pulldown Typical data is non-monotonic
> WARNING (line 49) - Pulldown Maximum data is non-monotonic <-
> WARNING (line 143) - Pullup Maximum data is non-monotonic
> WARNING (line 183) - Pullup Minimum data is non-monotonic
> WARNING (line 185) - Pullup Typical data is non-monotonic
> WARNING - Model 'Buffer1': TYP AC Falling Endpoints ( 0.87V, 3.30V) not within
> 0.049V (2%) of ( 0.77V, 3.30V) on VI curves for 50 Ohms to 3.3V
> WARNING - Model 'Buffer1': MIN AC Falling Endpoints ( 0.93V, 3.28V) not within
> 0.047V (2%) of ( 0.84V, 3.29V) on VI curves for 50 Ohms to 3.3V
> WARNING - Model 'Buffer1': MAX AC Rising Endpoints (-0.00V, 1.85V) not within
> 0.037V (2%) of (-13.50V, 1.87V) on VI curves for 50 Ohms to 0V
> ???????
> WARNING - Model 'Buffer1': MAX AC Falling Endpoints ( 0.81V, 3.30V) not within
> 0.050V (2%) of (-15.70V, 3.30V) on VI curves for 50 Ohms to 3.3V
> ???????
> Errors : 0
> Warnings: 9
> ----------------------------------------------------------------------------------
>
> Pulldown Maximum data corrected.
>
> WARNING (line 47) - Pulldown Typical data is non-monotonic
> WARNING (line 143) - Pullup Maximum data is non-monotonic
> WARNING (line 183) - Pullup Minimum data is non-monotonic
> WARNING (line 185) - Pullup Typical data is non-monotonic
> WARNING - Model 'Buffer1': TYP AC Falling Endpoints ( 0.87V, 3.30V) not within
> 0.049V (2%) of ( 0.77V, 3.30V) on VI curves for 50 Ohms to 3.3V
> WARNING - Model 'Buffer1': MIN AC Falling Endpoints ( 0.93V, 3.28V) not within
> 0.047V (2%) of ( 0.84V, 3.29V) on VI curves for 50 Ohms to 3.3V
> WARNING - Model 'Buffer1': MAX AC Falling Endpoints ( 0.81V, 3.30V) not within
> 0.050V (2%) of ( 0.70V, 3.30V) on VI curves for 50 Ohms to 3.3V
> ^^^^^
> Errors : 0
> Warnings: 7
> --------------------------------------------------------------------------------
>
> Best regards.
>
> Shigeto Nakajima
> NEC Corpration
>
> shigeto@saed.tmg.nec.co.jp
Received on Mon May 18 17:06:50 1998