[IBIS-Users] Rref_diff keyword

From: Cynthia Low <ibis_user_at_.....>
Date: Mon Jul 06 2009 - 03:20:29 PDT
Dear IBIS experts
 
I am currently looking at the Rref_diff subparameters under the [model] keyword and the usage of this subparameters. This subparameters is only available in IBIS specification of v4.1 but not in older version. May I know how this subparameters keyword is being used? the detail of the question is as below.
 
IBIS Spec:
Rref_diff is used for true differential buffer timing test loads. where the buffer hv to be specified only when the [Diff Pin]
keyword connects two models, and each buffer references the same model.  The Rref_diff and Cref_diff subparameters can be used with the Rref, Cref, and Vref subparameters for a combined differential and signal-ended timing test load.

1. My questions will be, can this Rref_diff sub-parameters be used ONLY when we engaged using the true differential [External Model] with either spice or vhdl-ams? As shown in the IBIS spec.

2. Can this Rref_diff keyword be used in the context of a normal true differential buffer under the [Model] keyword, and at the same time the model is define under [Diff Pin] section to describe the timing test loads just like how the rest of the Cref, Vref keyword are used to facilitate for board-level timing simulation, with the setup as attached. Can the Rref_diff keyword used under the example below?  


[Model] 25_lvds
Model_type Output
Polarity Non-Inverting
Enable Active-Low
Rref_diff = 100
Vmeas = 1.163
C_comp  1.8pF   1..8pF  1.8pF   

Please kindly comment. Thanks. 

Regards
Cynthia


      
-- 
This message has been scanned for viruses and
dangerous content by MailScanner, and is
believed to be clean.




--------------------------------------------------------------------
|For help or to subscribe/unsubscribe, e-mail majordomo@eda-stds.org
|with 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 e-mail a request to ibis-request@eda-stds.org.
|
|IBIS reflector archives exist under:
|
|  http://www.eda-stds.org/pub/ibis/email_archive/ Recent
|  http://www.eda-stds.org/pub/ibis/users_archive/ Recent
|  http://www.eda-stds.org/pub/ibis/email/         E-mail since 1993
Received on Mon Jul 6 03:22:20 2009

This archive was generated by hypermail 2.1.8 : Mon Jul 06 2009 - 03:23:40 PDT