RE: [IBIS-Users] possible ibis golden parser bug

Hi Ramiro

From the errors and warnings it looks like your V-t waveform has not reached
its full value. This is most likely because of insufficient simulation time.

My GUESS is that your initial simulation when everything passed is actually
high drive. Your second simulation is probably your low drive. Since you say
that you haven't changed anything other than the enable, I'm assuming that
you did not change the simulation time.
I could be completely wrong but can you check if you are selecting the
correct enables for high/low drive. Try increasing the simulation time.

Prabhu

-----Original Message-----
From: RODRIGUEZ_LECONA_RAMIRO [mailto:rlecona@siu.buap.mx]
Sent: Wednesday, October 27, 2004 12:18 PM
To: ibis-info@eda.org; ibis-users@eda.org
Subject: [IBIS-Users] possible ibis golden parser bug

Hi all:

    I am generating a IBIS model for an output buffer, and I have a STRANGE
problem. I have an output buffer with low drive/high drive options, they are

selected by activate an enable pin. I get all curves for output buffer low
drive option and check the syntax and construction with IBISCHK3 V3.2.9
and the model passes without errors or warnings. But when I active the high
drive option and again get all curves for the output buffer the IBISHK3
gives several errors and warnings. The only thing that I changed was the
enable voltage !!!
     What happen?
      It is possible that the parser IBISCHK3 V3.2.9 has a bug?
      Or my model is not correctly constructed? But if this the case, why
when I check the model for low drive the parser does not give errors o
warnings?

       Here the error list that I obtain from IBISCHK3:

WARNING - Model OUTPUT: POWER Clamp : Typical value never becomes zero
WARNING - Model OUTPUT: POWER Clamp : Minimum value never becomes zero
WARNING - Model OUTPUT: POWER Clamp : Maximum value never becomes zero
ERROR - Model OUTPUT: The [Rising Waveform]
     with [R_fixture]=50 Ohms and [V_fixture]=3.3V
     has TYP column DC endpoints of 0.73V and 3.30v, but
     an equivalent load applied to the model's I-V tables yields
     different voltages ( 0.22V and 1.45V),
     a difference of 41.16% and 150.48%, respectively.
ERROR - Model OUTPUT: The [Rising Waveform]
     with [R_fixture]=50 Ohms and [V_fixture]=0V
     has TYP column DC endpoints of 0.00V and 2.56v, but
     an equivalent load applied to the model's I-V tables yields
     different voltages (-0.42V and 0.21V),
     a difference of 67.04% and 373.91%, respectively.
ERROR - Model OUTPUT: The [Falling Waveform]
     with [R_fixture]=50 Ohms and [V_fixture]=3.3V
     has TYP column DC endpoints of 0.73V and 3.30v, but
     an equivalent load applied to the model's I-V tables yields
     different voltages ( 0.22V and 1.45V),
     a difference of 41.16% and 150.48%, respectively.
ERROR - Model OUTPUT: The [Falling Waveform]
     with [R_fixture]=50 Ohms and [V_fixture]=0V
     has TYP column DC endpoints of 0.00V and 2.56v, but
     an equivalent load applied to the model's I-V tables yields
     different voltages (-0.42V and 0.21V),
     a difference of 67.04% and 373.91%, respectively.
WARNING - Model 'OUTPUT': TYP VI curves cannot drive through Vmeas=1.65V
         given load Rref=50 Ohms to Vref=1.65V
ERROR - Model OUTPUT: The [Rising Waveform]
     with [R_fixture]=50 Ohms and [V_fixture_min]=3V
     has MIN column DC endpoints of 0.77V and 3.00v, but
     an equivalent load applied to the model's I-V tables yields
     different voltages ( 0.31V and 1.40V),
     a difference of 42.23% and 147.88%, respectively.
ERROR - Model OUTPUT: The [Rising Waveform]
     with [R_fixture]=50 Ohms and [V_fixture_min]=0V
     has MIN column DC endpoints of 0.00V and 2.17v, but
     an equivalent load applied to the model's I-V tables yields
     different voltages (-0.35V and 0.09V),
     a difference of 80.17% and 474.98%, respectively.
ERROR - Model OUTPUT: The [Falling Waveform]
     with [R_fixture]=50 Ohms and [V_fixture_min]=3V
     has MIN column DC endpoints of 0.77V and 3.00v, but
     an equivalent load applied to the model's I-V tables yields
     different voltages ( 0.31V and 1.40V),
     a difference of 42.27% and 147.88%, respectively.
ERROR - Model OUTPUT: The [Falling Waveform]
     with [R_fixture]=50 Ohms and [V_fixture_min]=0V
     has MIN column DC endpoints of 0.00V and 2.17v, but
     an equivalent load applied to the model's I-V tables yields
     different voltages (-0.35V and 0.09V),
     a difference of 80.17% and 475.12%, respectively.
WARNING - Model 'OUTPUT': MIN VI curves cannot drive through Vmeas=1.65V
         given load Rref=50 Ohms to Vref=1.65V
ERROR - Model OUTPUT: The [Rising Waveform]
     with [R_fixture]=50 Ohms and [V_fixture_max]=3.6V
     has MAX column DC endpoints of 0.72V and 3.60v, but
     an equivalent load applied to the model's I-V tables yields
     different voltages ( 0.16V and 1.55V),
     a difference of 40.41% and 147.58%, respectively.
ERROR - Model OUTPUT: The [Rising Waveform]
     with [R_fixture]=50 Ohms and [V_fixture_max]=0V
     has MAX column DC endpoints of 0.00V and 2.90v, but
     an equivalent load applied to the model's I-V tables yields
     different voltages (-0.49V and 0.34V),
     a difference of 59.18% and 307.62%, respectively.
ERROR - Model OUTPUT: The [Falling Waveform]
     with [R_fixture]=50 Ohms and [V_fixture_max]=3.6V
     has MAX column DC endpoints of 0.72V and 3.60v, but
     an equivalent load applied to the model's I-V tables yields
     different voltages ( 0.16V and 1.55V),
     a difference of 40.41% and 147.58%, respectively.
ERROR - Model OUTPUT: The [Falling Waveform]
     with [R_fixture]=50 Ohms and [V_fixture_max]=0V
     has MAX column DC endpoints of 0.00V and 2.90v, but
     an equivalent load applied to the model's I-V tables yields
     different voltages (-0.49V and 0.34V),
     a difference of 59.18% and 307.62%, respectively.
WARNING - Model 'OUTPUT': MAX VI curves cannot drive through Vmeas=1.65V
         given load Rref=50 Ohms to Vref=1.65V
Errors : 12

Warnings : 6

File Failed

          Best regards,

          Ramiro R. Lecona

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Received on Wed, 27 Oct 2004 12:37:13 -0700