[IBIS-Users] RE: on-die termination ... one more time

Ramiro,

Thanks for the message.  I re-read my original text and, at the risk of
embarrassment, can only conclude I made a very misleading statement.

My *intent* was to say that there was no requirement in the parser or
the specification for I-V curves to *pass through the origin* (0 V, 0
A).  In fact, as I stated, one of your clamp curves will not pass
through the origin if you include an internal termination and account
for it in the [POWER Clamp] and [GND Clamp] I-V tables.

I have performed some experiments and find that the parser *does indeed*
check that the current data "becomes zero" (or at least to become within
1e-6 A of zero).  Honestly, I had never seen this warning before in
almost ten years of creating and checking IBIS models.

To my knowledge, there is no requirement explicit in the specification
for this, but it's definitely a good idea from a design perspective.
Comments and elaborations on this here on the reflector are welcome.

I hope this helps and sorry for the confusion.

- Michael Mirmak
  Intel Corp.
  Chair, EIA IBIS Open Forum
  

-----Original Message-----
From: owner-ibis-info@eda.org [mailto:owner-ibis-info@eda.org] On Behalf
Of RODRIGUEZ_LECONA_RAMIRO
Sent: Thursday, February 17, 2005 11:02 AM
To: ibis-users@eda.org; ibis-info@eda.org
Subject: on-die termination ... one more time

Hi all, 

    Thank you by your answers. I am generating an IBIS model that
includes 
an input structure with a pull-up resistor. I include the pull-up
resistor 
characteristics in the ground clamp curve but when I check the IBIS file

with IBIS parser (IBISCHK3 v3.2.9) the parser  gives the warning:
"WARNING - 
Model Input02: GND Clamp : Maximum value never becomes zero".
    Michael Mirmak said that there is no requirement for all clamp
curves to 
"reach the zero value" then what is the cause for this Warning? 

                                      Thank you 

Best Regards 

Ramiro

|------------------------------------------------------------------
|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