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 |------------------------------------------------------------------ |For help or to subscribe/unsubscribe, email majordomo@eda.org |with just the appropriate command message(s) in the body: | | help | subscribe ibis <optional e-mail address, if different> | subscribe ibis-users <optional e-mail address, if different> | unsubscribe ibis <optional e-mail address, if different> | unsubscribe ibis-users <optional e-mail address, if different> | |or email a written request to ibis-request@eda.org. | |IBIS reflector archives exist under: | | http://www.eda.org/pub/ibis/email_archive/ Recent | http://www.eda.org/pub/ibis/users_archive/ Recent | http://www.eda.org/pub/ibis/email/ E-mail since 1993Received on Thu Sep 8 15:26:45 2005
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