Ahmed,
It is not the frequency that counts, it is the edge rate.
In this day of age, most devices have very fast edge rates
(unless they have slew rate control features), and even if
you run them at low frequencies, the transmission line will
behave and look like as a transmission line, not as a
capacitance.
Thanks,
Arpad
===============================================================
From: ibis-users-bounce@xxxxxxxxxxxxx [mailto:ibis-users-bounce@xxxxxxxxxxxxx] ;
On Behalf Of Ahmed Essam
Sent: Friday, April 22, 2016 12:58 PM
To: Mike LaBonte <mlabonte@xxxxxxxxxx>
Cc: ibis-users@xxxxxxxxxxxxx; ibis@xxxxxxxxxxxxx
Subject: [ibis-users] Re: Buffer with standard capacitive load
Hi Mike,
I am trying to model a buffer operating at low frequencies at which the
transmission line is modeled as a capacitor
Thanks
Ahmed
On Fri, Apr 22, 2016 at 7:41 PM, Mike LaBonte
<mlabonte@xxxxxxxxxx<mailto:mlabonte@xxxxxxxxxx>> wrote:
Hi Ahmed,
In general capacitive loads are not used in the process of making IBIS models.
The *_fixture subparameters are intended to represent an RLC through which he
buffer was measured, usually in actual bench testing. The simulator must
de-embed them, in general use of them is discouraged. You might try to give
more details about what you are trying to accomplish, and why a capacitive load
is involved.
Mike
From: ibis-users-bounce@xxxxxxxxxxxxx<mailto:ibis-users-bounce@xxxxxxxxxxxxx>
[mailto:ibis-users-bounce@xxxxxxxxxxxxx<mailto:ibis-users-bounce@xxxxxxxxxxxxx>]
On Behalf Of Ahmed Essam
Sent: Friday, April 22, 2016 1:17 PM
To: ibis-users@xxxxxxxxxxxxx<mailto:ibis-users@xxxxxxxxxxxxx>;
ibis@xxxxxxxxxxxxx<mailto:ibis@xxxxxxxxxxxxx>
Subject: [ibis-users] Buffer with standard capacitive load
Hi All,
i am trying to make an IBIS model for an output buffer with a capacitive load.i
found a big difference between rise time between schematics and IBIS model.i
have inserted R_fixture=50 ohm for making IBIS moddel for that buffer.Should i
insert C_fixture also ?
Thanks,
Ahmed