Arpad-san,
Thank you for your information.
My model is a pseudo differential model.
(Positive and negative pins are described in a [Diff_pin].)
In that model, I understand that Zo(resisters) are modeled as R_fixture in
Rising/Falling waveforms.
If I add the another(dummy) pin to the IBIS model, Can I connect the pin to
a node between two resistors?
(Please refer to a part of a dotted line of attached material.)
Best Regards.
Kazunori Yamada.
Renesas Electronics Corp.
From: Muranyi, Arpad <Arpad_Muranyi@xxxxxxxxxx>
Sent: Thursday, July 19, 2018 12:12 AM
To: Kazunori Yamada <kazunori.yamada.ux@xxxxxxxxxxx>; ibis-users@xxxxxxxxxxxxx
Cc: MASARU ENOMOTO <masaru.enomoto.zn@xxxxxxxxxxx>; HIROYOSHI KUGE
<hiroyoshi.kuge.vx@xxxxxxxxxxx>
Subject: RE: [Please help me!!] Question about capacitance between termination
and gnd.
Kazunori,
You are correct, you cannot model that capacitance with [C Series] the
way you drew your block diagram. But if you had another (dummy) pin
for the node between the two resistors to which the capacitor is connected,
you could use [C Series] from that pin to a GND pin. Another question is
how you are modeling the Tx buffer. As a pseudo differential model or
a true differential model? If the latter, you will need to use [External
Model], and in that you can model those resistors and capacitor any way
you want.
A third question is where is the "GND" side of the capacitor connected?
You show a ground symbol on your block diagram, but what is that in your
simulation? Is it the SPICE "node 0"? You may want to consider using one
of the buffer's reference terminals instead...
I hope this helps,
Arpad
==========================================================
From: ibis-users-bounce@xxxxxxxxxxxxx<mailto:ibis-users-bounce@xxxxxxxxxxxxx>
[mailto:ibis-users-bounce@xxxxxxxxxxxxx] On Behalf Of Kazunori Yamada
Sent: Wednesday, July 18, 2018 1:50 AM
To: ibis-users@xxxxxxxxxxxxx<mailto:ibis-users@xxxxxxxxxxxxx>
Cc: MASARU ENOMOTO
<masaru.enomoto.zn@xxxxxxxxxxx<mailto:masaru.enomoto.zn@xxxxxxxxxxx>>;
HIROYOSHI KUGE
<hiroyoshi.kuge.vx@xxxxxxxxxxx<mailto:hiroyoshi.kuge.vx@xxxxxxxxxxx>>
Subject: [ibis-users] [Please help me!!] Question about capacitance between
termination and gnd.
Hi experts.
Please let me know if capacitance (CCM) between
differential termination and gnd can be modeled in IBIS.
I wrote the details in the attached material.
I think that the capacitance can't be modeled by using
[C Series].
Thanks for your support.
Best Regards.
Kazunori Yamada.
Renesas Electronics Corp.
Attachment:
Questions for IBIS model_20180719_2.pdf
Description: Questions for IBIS model_20180719_2.pdf
