RE: [IBIS-Users] IBISCHK4

From: Abril, Giovanni \(Space Technology\) <giovanni.abril_at_.....>
Date: Thu Sep 08 2005 - 15:25:45 PDT
Hi Joe,
 
Is it possible your VT table terminates before the transition is complete?  The DC endpoints seem pretty far off.  I don't recall the details, but there was a Cadence application note on this from a few years back, I think Lynne Green might have written it that explains how the calculation is made, but basically the checker will compare your IBIS model endpoints to a 'loadline' based on R_fixture/V_fixture and the IV data in your IBIS model.  If the endpoints are off by more than some threshold (2%?) ibischeck isn't happy.
 
I think Lynne responds to these emails and might be able to provide further insight.
 
Gio

________________________________

From: owner-ibis-users@eda.org on behalf of Guimont, Joe G (MN14)
Sent: Thu 9/8/2005 10:26 AM
To: ibis-users@eda.org
Subject: [IBIS-Users] IBISCHK4



Hi,

 

In checking a bipad IBIS model (I/O) that was generated from a Spectre netlist I keep getting the following errors and have been unable to resolve them and would like any input as to the origin of such errors.  In addition, I have varied the [R_fixture] from 50, 1k and 1meg and get the same results. 

 

IBISCHK4 V4.1.1

 

Checking bipad.ibs for IBIS 3.2 Compatibility...

 

WARNING (line   64) - Pulldown Maximum data is non-monotonic

WARNING (line   65) - Pulldown Typical data is non-monotonic

WARNING (line   67) - Pulldown Minimum data is non-monotonic

WARNING (line  142) - Pullup Maximum data is non-monotonic

WARNING (line  143) - Pullup Typical data is non-monotonic

WARNING (line  145) - Pullup Minimum data is non-monotonic

ERROR - Model bipad: The [Rising Waveform] 

      with [R_fixture]=1000 Ohms and [V_fixture]=0V

      has TYP column DC endpoints of  0.00V and  3.23v, but

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

      different voltages ( 1.70V and  3.27V),

      a difference of 108.75% and  2.01%, respectively.

ERROR - Model bipad: The [Rising Waveform] 

      with [R_fixture]=1000 Ohms and [V_fixture]=3.3V

      has TYP column DC endpoints of  0.06V and  3.30v, but

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

      different voltages ( 1.74V and  3.30V),

      a difference of 107.92% and  0.00%, respectively.

ERROR - Model bipad: The [Falling Waveform] 

      with [R_fixture]=1000 Ohms and [V_fixture]=3.3V

      has TYP column DC endpoints of  0.06V and  3.30v, but

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

      different voltages ( 1.74V and  3.30V),

      a difference of 107.92% and  0.00%, respectively.

ERROR - Model bipad: The [Falling Waveform] 

      with [R_fixture]=1000 Ohms and [V_fixture]=0V

      has TYP column DC endpoints of  0.00V and  3.23v, but

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

      different voltages ( 1.70V and  3.27V),

      a difference of 108.75% and  2.01%, respectively.

WARNING - Model 'bipad': TYP VI curves cannot drive through Vmeas=1.65V

          given load Rref=1e+12 Ohms to Vref=0V

ERROR - Model bipad: The [Rising Waveform] 

      with [R_fixture]=1000 Ohms and [V_fixture_min]=0V

      has MIN column DC endpoints of  0.00V and  2.92v, but

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

      different voltages ( 1.82V and  2.96V),

      a difference of 159.10% and  3.61%, respectively.

ERROR - Model bipad: The [Rising Waveform] 

      with [R_fixture]=1000 Ohms and [V_fixture_min]=3V

      has MIN column DC endpoints of  0.08V and  3.00v, but

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

      different voltages ( 1.87V and  3.00V),

      a difference of 158.74% and  0.00%, respectively.

ERROR - Model bipad: The [Falling Waveform] 

      with [R_fixture]=1000 Ohms and [V_fixture_min]=3V

      has MIN column DC endpoints of  0.08V and  3.00v, but

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

      different voltages ( 1.87V and  3.00V),

      a difference of 158.74% and  0.00%, respectively.

ERROR - Model bipad: The [Falling Waveform] 

      with [R_fixture]=1000 Ohms and [V_fixture_min]=0V

      has MIN column DC endpoints of  0.00V and  2.92v, but

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

      different voltages ( 1.82V and  2.96V),

      a difference of 159.10% and  3.60%, respectively.

WARNING - Model 'bipad': MIN VI curves cannot drive through Vmeas=1.65V

          given load Rref=1e+12 Ohms to Vref=0V

ERROR - Model bipad: The [Rising Waveform] 

      with [R_fixture]=1000 Ohms and [V_fixture_max]=0V

      has MAX column DC endpoints of  0.00V and  3.54v, but

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

      different voltages ( 1.62V and  3.57V),

      a difference of 83.40% and  1.26%, respectively.

ERROR - Model bipad: The [Rising Waveform] 

      with [R_fixture]=1000 Ohms and [V_fixture_max]=3.6V

      has MAX column DC endpoints of  0.05V and  3.60v, but

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

      different voltages ( 1.66V and  3.60V),

      a difference of 82.68% and  0.00%, respectively.

ERROR - Model bipad: The [Falling Waveform] 

      with [R_fixture]=1000 Ohms and [V_fixture_max]=3.6V

      has MAX column DC endpoints of  0.05V and  3.60v, but

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

      different voltages ( 1.66V and  3.60V),

      a difference of 82.68% and  0.00%, respectively.

ERROR - Model bipad: The [Falling Waveform] 

      with [R_fixture]=1000 Ohms and [V_fixture_max]=0V

      has MAX column DC endpoints of  0.00V and  3.54v, but

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

      different voltages ( 1.62V and  3.57V),

      a difference of 83.40% and  1.26%, respectively.

 

Errors  : 12

Warnings: 8

 

File Failed

 

Joe Guimont

SRAM Design

Honeywell Defense & Space Electronic Systems

12001 Highway 55 (C318)

Plymouth, MN 55441

Phone 763-954-2512

Fax 763-954-2742

joe.guimont@honeywell.com

 

 


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Received on Thu Sep 8 15:26:45 2005

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