Subject: Re: Bird 17, 101 points in tables

From: Arpad Muranyi <[email-masked]>
Date: Mon, 25 Jul 94 10:03:04 PST

Hi all,

Since I missed the last IBIS open forum meeting due to vacationing, I am not 
sure what the background of BIRD 17 is.

Even though I do not like the 100 point limitation in some ways, I still think 
it might be necessary because of the 100 point limit in the SPICE PWL sources.  
As far as I understand, if we allow more than 100 points, we would automatically
exclude IBIS models to be used under SPICE platforms.  (Let me know if I am 
wrong).

Since most curves have slowly changing (less sharp corners), or flat regions, I 
think it is not necessary to use fine (0.1V) increments throughout the whole 
range of a curve.  Even though it is additional work, it is possible to write a 
simple algorythm which increases the data points in quickly changing areas and 
reduces them elsewhere.

Arpad Muranyi
Intel Corporation

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From: Scott Aron Bloom <[email-masked]>
Date: Mon, 25 Jul 1994 13:17:56 -0700

Arpad, 

   Thank you for your feedback.  After speaking with a Spice Simulator
vendor, you concern was verified.  There is a 100 point voltage pair
limit on PWL power supplies.  Based on this new information :^), Bob and
I would now oppose BIRD 17. Therefore, the bird will be revoked.

Scott Bloom
InterConnectiX, Inc.

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From: [email-masked] (Jon Powell)
Date: Mon, 25 Jul 94 17:07:15 PDT

About SPICE limitations etc:
I don't really care if we allow more than 100 points but I don't think that
SPICE (or any other simulator) limitations should be a consideration when making 
IBIS rules. If data wants to be in a certain format we should let it be that way
and let the simulator companies force it into the proper format.
I bet that if the SPICE companies got 200 point arrays they would figure out
a way to get 100 good points out of it.

jonp