Subject: [IBIS-Users] Modelling an open drain driver
From: Henrik G. Madsen (hgm@vitesse.com)
Date: Thu Nov 21 2002 - 04:20:11 PST
Hey
I'm trying to make an IBIS model (from SPICE) for an open drain driver.
The driver is powered from 2.5V and the Vpullup is either 2.5V or 3.3V.
I have tried to sketch the end user application below
___Vpullup
|
|
/
\ Rpullup __________
OD driver / | |
\ ____________ | |
______.___|____| 60 ohm |_____| Receiver |
| |____________| | |
_| | |
-|_ |__________|
|
|
|__ VSS
|
-----Driver---|-----------normal use circuit--------------
I'm in doubt how to write the S2IBIS setup file (.s2i) for an OD driver.
I know that I should use the 'Open_sink' modeltype, but how should I define the rising and falling waveforms.
I would assume that R_fixture = 60 ohm and V_fixture = 0V
Moreover I imagine that I should only do the falling waveform and not the rising, which would be controlled by the external pullup resistor.
_____________________________________
Henrik G Madsen
Sr. HW Engineer
Vitesse Semiconductor Corporation A/S
Ethernet Products Division
Hoerkaer 16, DK-2730 Herlev, DENMARK
Direct: +45 4485 5920
Phone: +45 4485 5900, Fax: +45 4485 5901
mail: hgm@vitesse.com
web: http://www.vitesse.com
_____________________________________
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