All,
Let me explain the intent of asking this question. IBIS describes
measurements of a Device Under Test. For the normal IBIS model that has
[Voltage Range] the [Pullup Reference] and [Power Clamp Reference] voltage
applied during measurements (or virtual measurements using the SPICE to
IBIS process) are by definition measurements relative to the Test Fixture
Reference Voltage 0.0V, also called "Absolute Ground" in IBIS. The
pulldown terminal and/or gnd clamp terminal of the DUT are connected
directly to this "Absolute Ground". THEREFORE the node at the pulldown
terminal and/or gnd clamp terminal is also the reference for all IV, VT,
and threshold measurements of the DUT.
When this buffer is used in actions (Device In Action -DIA). Then is it
not natural to assume that the node at the pulldown terminal and/or gnd
clamp terminal of a DIA should be the reference node for all measurements
at the device I/O pad and Pullup and Power Clamp terminals.
Walter
From: Walter Katz [mailto:wkatz@xxxxxxxxxx] ;
Sent: Tuesday, May 31, 2016 2:17 PM
To: IBIS-ATM <ibis-macro@xxxxxxxxxxxxx>
Subject: basic question about voltages at an I/O buffer.
All,
The specific I/O buffer has two rail voltages (VDD and VSS), and an I/O
port (IO).
Do you agree that the operation of this buffer is only a function of two
of the following three voltages?
1. VDD-VSS
2. VDD-IO
3. VSS-IO
Walter
Walter Katz
<mailto:wkatz@xxxxxxxxxx> wkatz@xxxxxxxxxx
Phone 303.449-2308
Mobile 303.335-6156
