RE: [IBIS-Users] differential receiver ibis model

Raghavendra,

The common mode current goes into the normal [Model]'s
I-V tables, and the differential current goes into the
series model that is placed between the two [Model]-s.
You can further separate the clamp currents from the
PU and PD I-V curves in the [Model] by redoing the
same measurements in a 3-stated mode.  (But don't
forget to put the difference of the clamp and driven
I-V curves into the PU and PD tables, instead of the
total current to avoid double counting).

I am not aware of a tool that can do all this in
an automated way.

Arpad
=======================================================

-----Original Message-----
From: owner-ibis-users@server.eda.org
[mailto:owner-ibis-users@server.eda.org] On Behalf Of Raghavendra M
Sent: Thursday, September 10, 2009 12:17 AM
To: ibis-users@server.eda.org
Subject: [IBIS-Users] differential receiver ibis model

Hi,

I have a fully differential receiver in a chip, am trying to make an 
ibis model for this receiver
Can you describe the method how to generate an ibis v3 model for the 
differential receiver
I read the ibis cookbook and it says that for a differential buffer with

positive and negative inputs,
one input should be swept keeping the other input constant(negative) and

record the currents into both inputs.
Now change the constant input to new value and sweep the positive input 
and record the currents.
This process should be continued as the negative input is swept in steps

through the  same range  as positive input.
 From the current recorded we have to separate common mode and 
differential mode currents.
But my question is where should we keep this common mode and 
differential mode currents in the ibis file?
Actually for receiver, only clamp data should be kept in ibis file, so 
in [Power clamp] data where should we keep
common mode current and differential mode current

Should i use series model for my differential receiver?
Should we place these characteristics in the model series?
Is there any tool to generate an ibis model for differential receiver 
directly?

Thanks & Regards
Raghavendra M


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