RE: [IBIS-Users] Non-monotonic data - pullup/down, OUTPUT only model ??

From: Lynne D. Green <lgreen22_at_.....>
Date: Tue May 23 2006 - 10:42:35 PDT
Hello,  Mithlesh,

If you would like to have your model reviewed, you are welcome to send it to
the IBIS Model Review Committee (information at
http://www.eigroup.org/ibis/support.htm).

How much trouble non-monotonicity causes depends on the size of the
discontinuity and on the SI tool.  Large discontinuities cause more problems
for  more tools.  My personal rule of thumb is - if I can see it clearly on
a plot of the table data, it is probably too big.

Some possible causes of I-V table discontinuities: separation of clamp and
pullup/pulldown data (OK if non-monotonicity goes away when these are added
back together), SPICE and measurement tolerances, I/O circuit with internal
feedback, incorrect test circuit.

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@mindspring.com


-----Original Message-----
From: owner-ibis-users@eda.org [mailto:owner-ibis-users@eda.org] On Behalf
Of Mithlesh Shrivas-r64034
Sent: Tuesday, May 23, 2006 5:29 AM
To: ibis-users
Subject: [IBIS-Users] Non-monotonic data - pullup/down, OUTPUT only model ??

Hello All,

I was referring to a old discussions on non-monotonicity and collected
information that says these warnings are common for the Pullup and Pulldown
tables in I/O. If the IBIS file version is used 4.0 or higher, many these
warning could be removed which actually worked for IO.

In my case, the pulldown and pullup data are non-monotonic and if i
construct an Output type model which does not has Clamp data and therefore,
the non-monotonicity will always exist.

I'm attaching a section of pulldown/pullup data, please review it. I think
after -0.9, the behavior of data is good but problem exist before that.

Do you think that initial few non-monotonic data could create any problem?



Thanks
Mithlesh


--
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Mithlesh Shrivas (Core-id:R64034).......
Design Engineer.........................
Freescale Semiconductor India Pvt. Ltd..
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Sector- 16A, Noida- 201301 U.P. (India).
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"Analog circuit design is like chess -just because you know how the pieces
move doesn't mean you know how to play the game." --PATRICK M. LAHEY "To
become expert in analog circuit design, one should have `POWERFUL URGE TO
LEARN' 
and attitude of doing things Properly, Intelligently and Systematically,
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Received on Tue May 23 10:42:07 2006

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