[IBIS-Users] Buffer ramp rates & loading question.


Subject: [IBIS-Users] Buffer ramp rates & loading question.
From: John Phillippe (john.phillippe@motorola.com)
Date: Thu Feb 13 2003 - 15:20:25 PST


Hello People,
   I have a few quick questions below:

1. I have gotten a few warnings about the power clamp values that never
become zero. How can I fix the warnings?

WARNING - Model Pad_fc_drive10: POWER Clamp : Minimum value never
becomes zero

2. I have some slow I/O drivers that take a long time to settle for the
rising and falling curves. To help the curves settle faster, I want
to use 300 Ohms for the load. Normally I would use 50 Ohms load for the
I/O drivers. I am wondering if I can use 300 Ohms load for the slow
drivers? Is it going to be a simulator problem if some of the buffers
use 50 Ohm loads, and others 300 Ohms loads?

3. The keyword [Ramp] gives you the ramp rate on how long it takes the
output to switch from one state to another. It is define by 20% to 80%
voltage swing of the output to the time it takes to swing the voltage.
What is the pin loading used for this measurement?

-- 
John Phillippe
SPS, 32 Bit Embedded Controller Division, IC Creation
Motorola      -  512-895-1835
Austin, TX    -  john.phillippe@motorola.com

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