Yes the procedure described in 4.6.1 does not require resistors, it is a
straightforward current measurement (figure 4.13). Section 4.6 of the
cookbook has additional notes that are useful, as well as links to other
documents that give details and examples.
Mike
From: Ahmed Essam [mailto:aessam@xxxxxxxxx]
Sent: Thursday, April 21, 2016 9:30 AM
To: Mike LaBonte
Cc: ibis@xxxxxxxxxxxxx; ibis-users@xxxxxxxxxxxxx
Subject: Re: [ibis-users] IBIS model for differential buffers
Hi Mike,
Thanks for your reply. I have attached the buffer which i need to extract
IBIS model for. What i believe based on IBIS cookbook that i should model it
as a pseudo differential buffer as there is no on-die termination.so i can
model the buffer as a single ended buffer without the need to insert
termination between the 2 pads.(Adding 50 ohm resistance to single pad and
extracting the model then defining it in the IBIS model as pseudo
differential using Diff pin keyword ) OR i have to insert 100 ohm
termination resistance between the 2 pads then extract the model as a true
differential buffer
Thanks
Ahmed
On Thu, Apr 21, 2016 at 2:53 PM, Mike LaBonte <mlabonte@xxxxxxxxxx> wrote:
Hi Ahmed,
Have you consulted the IBIS Cookbook at http://ibis.org/cookbook/? Chapter 4 ;
covers extraction of differential buffers, and is quite comprehensive. For
differential buffers without on-die termination you need a test fixture with
termination, and the extracted model is valid for that termination scenario.
The cookbook describes that and more.
Mike
From: ibis-users-bounce@xxxxxxxxxxxxx
[mailto:ibis-users-bounce@xxxxxxxxxxxxx] On Behalf Of Ahmed Essam
Sent: Thursday, April 21, 2016 5:19 AM
To: ibis@xxxxxxxxxxxxx; ibis-users@xxxxxxxxxxxxx
Subject: [ibis-users] IBIS model for differential buffers
Hi All,
i just started learning about ibis models and i want to make an ibis model
for differential buffer.
i get confused about modeling the differential buffer as a pseudo
differential or true differential.
What i get from my readings about true differential buffer there is a path
for current between pads of buffer.
The buffer that i want to make an ibis model for has no on-die termination
between the 2 pads.but the termination resistance is connected in series
with pull up and pull down devices .
so there is no path for current between the two pads expect for when i
connect a termination resistance between the 2 pads to model the
transmission line impedance.
Shall i consider that buffer as a pseudo differential or as a true
differential buffer?
Thanks,
Ahmed
