From: Willis, Ken ([email protected])
Date: Mon Feb 19 2001 - 05:35:19 PST
Hi Hemant,
Where I have seen this used is to terminate differential pairs, for example
with
100 ohms across them. In these cases, the IOCell VI curves for the receiver
will generally not include these resistors, although they may have curves
for
clamp diodes if they exist. Then there will be a couple of other sections in
the IBIS file that define the diff pair associations, and the 100 ohm
differential
termination, like this:
[Diff Pin] inv_pin vdiff tdelay_typ tdelay_min tdelay_max
|
A1 B2 NA 0.000ns 0.000ns 0.000ns
E6 F7 0.100V 0.000ns 0.000ns 0.000ns
|
[Series Pin Mapping] pin_2 model_name function_table_group
E6 F7 100_ohm_diff
|
|************************************************************************
| Model 100_ohm_diff
|************************************************************************
[Model] 100_ohm_diff
Model_type Series
|
| variable typ min max
C_comp 0.00pF 0.00pF 0.00pF
[Voltage Range] 0.0V 0.0V 0.0V
[R Series] 100ohm 90ohm 110ohm
|
| End [Model] 100_ohm_diff
|
Many (OK, most) times the IBIS file will come without this stuff in it, and
you will
have to read through your data sheet and fix the IBIS file up to include
these items.
Ken
-----Original Message-----
From: Hemant Fulsunge [mailto:[email protected]]
Sent: Monday, February 19, 2001 11:52 AM
To: [email protected]
Subject: [SI-LIST] : Internal Temination
Hello SI Experts,
I have a question regarding the inbuilt termination for
a device.
1. Where does it show up in the IBIS file or where else can I find the
relevant information for the same?
Awaiting to hear your answers soon.
Regards
hemant
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