Mei-Yee,
Can you expand on the phrase "the netlist I used for the pad is an
extracted netlist"?
Do you mean the transistor-level netlist used to create the IBIS buffer
model in the first place ... that is, a transistor level netlist used
to perform simulation under controlled conditions, the results of which
were post-processed to create the IBIS buffer model?
If that's what you meant,
and the
transistor level netlist you started with included the output buffer's
capacitance, then the conversion program (s2ibis3 or other) you used
should have calculated and included C_Comp automatically in your buffer
model. Arpad is correct that the V-T curves in the IBIS model should
include the effects of C_Comp, and the IBIS simulator needs to combine
the V-T data and C_Comp during simulation without double-counting the
effect of C_Comp.
... but I'm trying to understand whether your question was whether or
not C_Comp was to be added explicitly to the original transistor level
netlist. The usual answer to that question is - no.
Todd.
Todd Westerhoff
VP, Software Products
SiSoft
6 Clock Tower Place, Suite 250
Maynard, MA 01754
(978) 461-0449 x24
twesterh@sisoft.com
www.sisoft.com
NG,MEI-YEE wrote:
Hi Arpad,
Just one
quick question, if the netlist I
used for the pad is an extracted netlist, does that mean the C_comp
value is
already incorporated inside (parasitics and all)? In that case, if I
still put
in an additional C_comp value, it would mean that I’m double-counting
the
C_comp?
Thank you.
Best regards,
Mei
Yee
MCPD,
Avago Technologies (Malaysia)
Tel no.:
+604-6108515
Timmy,
You can do it
either way, it depends on your needs.
If you want to
correlate to your SPICE model, match
it to that, if
you want to correlate to real life,
match it to your
measurements.
Arpad
====================================================
From:
owner-ibis@server.eda.org [mailto:owner-ibis@server.eda.org] On Behalf Of Timmy Leon
Sent: Thursday,
September 25, 2008
8:46 PM
To: ibis@server.eda.org
Cc:
ibis-users@server.eda.org
Subject: [IBIS] C_comp
value
I have a question regarding the c_comp value
that we should put in IBIS model. Should the c_comp value be based on
measurement, or can we tune value so that IBIS model correlate with its
spice model or measurements? Thank you.
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Received on Mon Sep 29 06:01:05 2008