RE: IBIS model creation

Well, the arithmetic in my table is correct. Note that the Max and Min rows do not use a vout sweep range of exactly -vcc to 2*vcc.
Instead, they use a range that is adjusted to make the vcc-relative data (vtable) line up. That makes the post-processing of the
data much easier, and I suspect that's why the s2ibis2 author(s) implemented it this way.

In your table, you are using exactly -vcc to 2*vcc for the min and max rows. As you note, the vcc-relative (vtable) data then do
not cover the same range.

In a quick search, I can't find where the voltage range is explicitly defined in the spec. Can you provide a pointer?

Regards,
Ross
-----Original Message-----
From: nikolai@avanticorp.com [mailto:nikolai@avanticorp.com]
Sent: Thursday, January 06, 2000 1:51 PM
To: ibis-users@eda.org
Subject: RE: IBIS model creation

Happy new year IBISians,

It's kind of silly but I can not reproduce arithmetics
from the attached email. Here is mine:

        Vcc Vout Vtable

min 3.0 from -3.0 to 6.0 from 6.0 to -3.0

typ 3.3 from -3.3 to 6.6 from 6.6 to -3.3

max 3.6 from -3.6 to 7.2 from 7.2 to -3.6

Vcc is derived from range (denoted Vpower below)

Vout changes from ( Vground - Vpower ) to (Vpower + Vpower )
(see spec.) e.g. from ( 0 - Vcc ) to 2*Vcc
             e.g. from -Vcc to 2*Vcc

Vtable = Vcc - Vout

Conclusion: spec is inconsistent in this part.

Nikolai Bannov
Hspice group
Avant! Corporation

:-) From owner-ibis@server.eda.org Wed Jan 5 12:36 PST 2000
:-) From: "Ross Pryor" <rpryor@nortelnetworks.com>
:-) To: "'Stephen Nolan'" <s-nolan1@ti.com>, <ibis-users@eda.org>
:-) Subject: RE: IBIS model creation
:-) Date: Wed, 5 Jan 2000 14:33:28 -0500
:-) MIME-Version: 1.0
:-) Content-Transfer-Encoding: 7bit
:-) X-Priority: 3 (Normal)
:-) X-MSMail-Priority: Normal
:-) Importance: Normal
:-) X-MimeOLE: Produced By Microsoft MimeOLE V4.72.2120.0
:-)
:-) Stephen,
:-)
:-) The data are tabulated after the vcc-relative calculation, vtable=vcc-vout. After the calculation, the data have the same range.
:-) For a pullup curve, the following table may help:
:-)
:-) (vout) (vtable)
:-) sweep vcc-relative
:-) corner vcc range range
:-) ------ --- ----- -------------
:-) min 3.0 -3.6 > 6.3 6.6 > -3.3
:-) typ 3.3 -3.3 > 6.6 6.6 > -3.3
:-) max 3.6 -3.0 > 6.9 6.6 > -3.3
:-)
:-) Regards,
:-) Ross
:-) --------------
:-) Ross Pryor
:-) Nortel Networks
:-) Billerica, MA
:-) (978) 288-3811
:-) ESN 248-3811
:-) rpryor@nortelnetworks.com
:-)
Received on Thu Jan 6 11:44:48 2000