Prabhu,
Your SPICE and IBIS first rising edges seem to match, which I suppose is good. However, I also notice that on the high-to-low transition there is a little "pre-shoot" that seems to be captured by both your IBIS and your SPICE models. I mean the little spike upwards just before the falling edge starts. Then, looking at the low-to-high transition, I see that your SPICE result has a similar pre-shoot, this time a small spike downwards before it starts rising. Your IBIS simulation does not have this feature. Such features can only be captured in IBIS using rising and falling waveforms. I suspect something is wrong with your rising waveform table.
Your results may depend on what IBIS simulator you are using. Examine your rising edge waveforms to see if the "pre-shoot" is there. If it is, and you do not see it in you simulations, then there is a bug in your simulator.
Christopher Reid
Mentor Graphics Corporation
-----Original Message-----
From: owner-ibis-users@server.eda.org [mailto:owner-ibis-users@server.eda.org] On Behalf Of Tom Dagostino
Sent: Monday, March 15, 2004 4:42 PM
To: 'Kannan'; 'Mohan, Prabhu'
Cc: 'Ibis-Users (E-mail)'
Subject: RE: [IBIS-Users] IBIS-SPICE correlation
I don't think that would work. Vil, Vih only operate on receivers, not drivers.
Tom Dagostino
Teraspeed Consulting Group LLC
Device Modeling Division
13610 SW Harness Lane
Beaverton, OR 97008
503-430-1065
tom@teraspeed.com <mailto:tom@teraspeed.com>
Teraspeed Consulting Group LLC
2926 SE Yamhill St.
Portland, OR 97214
http://www.teraspeed.com <http://www.teraspeed.com/>
-----Original Message-----
From: owner-ibis-users@server.eda.org [mailto:owner-ibis-users@server.eda.org]On Behalf Of Kannan
Sent: Monday, March 15, 2004 4:00 PM
To: Mohan, Prabhu
Cc: Ibis-Users (E-mail)
Subject: Re: [IBIS-Users] IBIS-SPICE correlation
Mohan,
Try adjusting the input levels Vil and Vih on the IBIS models. I think that will solve the problem.
Regards
Kannan
Mohan, Prabhu wrote:
Hi
I am trying to correlate IBIS vs. Spice. The simulation seems to be off on
the rising edge. IBIS seems to start switching a little bit earlier than
Spice on the rising edge (refer the attachment, red-IBIS, yellow-SPICE). I'm
not sure what is causing it. Does anyone have any suggestion as to where the
error might be coming from?
Thanks
Prabhu
-----Original Message-----
From: Muranyi, Arpad [mailto:arpad.muranyi@intel.com <mailto:arpad.muranyi@intel.com> ]
Sent: Friday, March 12, 2004 9:59 AM
To: Ibis-Users (E-mail)
Subject: [IBIS-Users] RE: Question regarding .pkg versus simple RLC
Frank,
>From a syntax point of view, you can make models with the
same exact data in all formats (if you use the lowest
common syntax). However, since the more elaborate formats
allow you more detail, chances are that you will not find
numerical matches. It will all depend on the extraction
methodologies, and assumptions.
Arpad Muranyi
Intel Corporation
==========================================================
-----Original Message-----
From: Frank Dunlap [mailto:owner-ibis-users@eda.org <mailto:owner-ibis-users@eda.org> ] On
Behalf Of Frank Dunlap
Sent: Wednesday, March 10, 2004 6:09 PM
To: Ibis-Users (E-mail)
Subject: Question regarding .pkg versus simple RLC
Presumably, a .pkg file provides "more" information than the simple
RLC in the [Pin] section of an IBIS model. Assuming that's the case, do
simulators actually take advantage of this additional information? Are
there cases where a .pkg file is preferred? Are there cases when it's
not preferred, such as where its added complexity may cause problems?
Furthermore, is there a straightforward relationship between RLC
values that would appear under the [Pin] section in an IBIS model, and
corresponding values that would appear in a .pkg file?
Here's an example from the [Pin] section of an IBIS model:
[Pin] signal_name model_name R_pin L_pin C_pin
AE6 HINT# V33OP 2.170 8.506nH 6.636pF
AE5 HRW# V33OP 2.165 8.475nH 5.865pF
C16 S_A00 V33OP 1.332 3.287nH 3.472pF
Here's an example from a .pkg file:
[Resistance Matrix] Banded_matrix
[Bandwidth] 0
[Row] 2255
1.74791e+000
[Row] 2253
1.74386e+000
..
[Inductance Matrix] Sparse_matrix
[Row] 2255
2255 1.21125e-008
2253 1.70009e-010
B19 1.73505e-010
[Row] 2253
2253 1.25283e-008
J21 1.22831e-010
F20 1.89512e-010
K21 4.09167e-010
..
[Capacitance Matrix] Sparse_matrix
[Row] 2255
2255 4.40327e-012
2253 -2.82931e-015
B19 -1.47570e-015
[Row] 2253
2253 4.33757e-012
J21 -1.04449e-014
F20 -2.65107e-015
K21 -8.93602e-015
The .pkg and [Pin] information are from two different data sets. I'm
sorry, but I don't have both .pkg and [Pin] information from a common
data set.
Thanks in advance for any guidance,
Frank
|------------------------------------------------------------------
|For help or to subscribe/unsubscribe, email majordomo@eda.org <mailto: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 <mailto:ibis-request@eda.org> .
|
|IBIS reflector archives exist under:
|
| http://www.eda.org/pub/ibis/email_archive/ <http://www.eda.org/pub/ibis/email_archive/> Recent
| http://www.eda.org/pub/ibis/users_archive/ <http://www.eda.org/pub/ibis/users_archive/> Recent
| http://www.eda.org/pub/ibis/email/ <http://www.eda.org/pub/ibis/email/> E-mail since 1993
|------------------------------------------------------------------
|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 1993
Received on Mon Mar 15 17:17:42 2004
This archive was generated by hypermail 2.1.8 : Mon Mar 15 2004 - 17:18:18 PST