Subject: Re: [IBIS-Users] How to determine Ccomp
From: erik.van.der.ven@philips.com
Date: Thu Aug 07 2003 - 00:29:12 PDT
Hello Dekker,
Thank you for your response. I meant determination of Ccomp by
simulations, sorry.
Best regards,
Erik.
Ir. Erik van der Ven
Room DB1032
Business Line Networking Infrastructure
Philips Semiconductors BV
Gerstweg 2
6534 AE Nijmegen
The Netherlands
Phone: +31-24-3534334
"Dekker Graden" <tarka@teraspeed.com>
08/06/03 06:11 PM
Please respond to "Dekker Graden"
To: Erik van der Ven/NYM/SC/PHILIPS@EMEA2
cc:
Subject: Re: [IBIS-Users] How to determine Ccomp
Classification:
Hello Erik
If your talking about getting Ccomp from measurements there is another way
of doing it that I have found to be quite good using a TDR. The
measurement method depends on if you have packaged or die only chips.
Anyway.... you just use a TDR to shoot in a pulse... then use something
like Iconnect (TDA systems software) to calculate what Ccomp is from the
waveform you get.
There are papers and application notes on http://www.tdasystems.com site that explain this way of getting Ccomp.
The only down side here is that you tend to only get the basic Ccomp...
about typical.
Anyway... just a pointer to a different direction if its an option for
you. The software and equipment is rather spendy.
Dekker
----- Original Message -----
From: erik.van.der.ven@philips.com
To: ibis-users@eda.org
Cc: cor.duijndam@philips.com
Sent: Wednesday, August 06, 2003 2:25 AM
Subject: [IBIS-Users] How to determine Ccomp
Dear IBIS collegues,
What is the best way to determine Ccomp?
Basically there are two ways: applying a ramp to the output terminal and
calculate Ccomp from the slew-rate, or connecting an inductor to the
output and calculate the Ccomp from the resonace frequency.
Which method gives the best results? > always, or application dependent?
How is this done for differential outputs. Outputs like LVDS have internal
feedback loops to control the common level. Must something be done with
the "other" output? Is the peaking a reliable measure for the value of
Ccomp, or may the added inductor shift the poles and zeros of the feedback
buffer due this load causing a peaking that is not just the parallel
connection of Ccomp and the test inductor?
With kind regards,
Ir. Erik van der Ven
Room DB1032
Business Line Networking Infrastructure
Philips Semiconductors BV
Gerstweg 2
6534 AE Nijmegen
The Netherlands
Phone: +31-24-3534334
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