[SI-LIST] Re: [IBIS-Users] ODT topics
- From: "lgreen" <lgreen22@xxxxxxxxxxxxxx>
- To: <Radovan.Vuletic@xxxxxxxxxxxx>
- Date: Fri, 1 Apr 2005 10:05:25 -0800
Hello, Radovan,
Here are some suggestions to get you started with IBIS.
* Review the training materials on the IBIS web site. If you are =
interested
in attending an IBIS class in the San Jose area, please let me know, =
since
one is in the planning stages.
* Replace s2ibis2 with s2ibis3. This fixes the double-counting problem.
* Validate your IBIS model against the IBIS Quality Checklist.
* Compare HSPICE IBIS simulation with transistor-level HSPICE simulation =
to
verify your IBIS model. Note that HSPICE does not include the default
package model in the netlist, so you will need to add this in manually =
when
you wish to include package effects.
* Send your IBIS file to the IBIS Review Committee. They can give you
valuable feedback.
Best regards,
Lynne
"IBIS training when you need it, where you need it."
Dr. Lynne Green
Green Streak Programs
http://www.greenstreakprograms.com
425-788-0412
lgreen22@xxxxxxxxxxxxxx
-----Original Message-----
From: owner-ibis-users@xxxxxxx [mailto:owner-ibis-users@xxxxxxx] On =
Behalf
Of Radovan.Vuletic@xxxxxxxxxxxx
Sent: Friday, April 01, 2005 6:50 AM
To: ibis-users@xxxxxxx
Subject: [IBIS-Users] ODT topics
Hi,
recently I have took responsibility for IBIS models in Memory Products =
of
Infineon and soon I have realised that it is very tricky.=20
There were generated some ODT IBIS models (for DDR2 with thevenin
impedance, not possible to separate Pull-up and Pull -down impedance) =
with
s2ibis2 as Inputs with Power and Ground Clamps curves. Everything was OK
until first customer were complaining that during his simulations our =
ODT
behave other than comparing to Samsung and Micron ODT's. After some 5-6
hours of frustrating analysis we have discovered that the "only" problem =
is
that neither the clamp curves are cut where they reach zero nor they are
extrapolated horizontally to 2*Vcc. As soon as we done that (cutting at
zero current and extrapolating to 2*Vcc) everything was OK. By the way, =
Mr.
Muranyi has nicely explained this procedure in his paper "Modeling =
on-die
terminations in IBIS (without double counting)". The problem that we =
have
experienced is obviously because of double counting of some data.
My question would be: what are simulators (e.g. HSPICE) really doing =
with
IBIS models (specially with Input models), how are data treated, what is =
the
algorithm of calculation (if designer was aware of this algorithm double
counting could be perhaps avoided)? Is it possible to get this things
written in electronic form or anywhere on Internet?=20
By the way, on IBIS summit Meeting in Munich in March (DATE 2005) =
somebody
mentioned something about some Cookbook for ODT's. Is there any =
estimation
when will this Cookbook appear?
Many thanks in advance for any help or advice,
Radovan Vuletic
Infineon Technologies AG
MP PD PDE
Room 03.911
Balanstra=DFe 73
D-81541 M=FCnchen
Phone: +49 (0)89 234 20108
Fax: +49 (0)89 234 27705
Fax (PC): +49 (0)89 234 955 5305=20
E-mail: radovan.vuletic@xxxxxxxxxxxx
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