3-D model topics

Hello Arpad and all others,

this is just a very short comment on our opinion
on the 3-D model topic.

We completely agree on the necessity to describe
the dynamical behavior of an output buffer by a
current / voltage / time relationship. Therefore
the black box approach seems ok.

Based on our experience it is not enough to
characterize an output by statical current /voltage
curves and some ramp times. For example, when you are
looking at the simulation of a buffer together with
a transmission line structure you have the problem
that the load impedance is a function of time
resp. current. This current depends on the behavior of
the connected transmission line.

Therefore, I agree with your opinion that the driver's output
impedance is also a function of the load impedance during the
switch of the buffer.

So we should work on the definition of the curves that are
most suitable to describe these dependencies and on a measurement
methodology to derive them.

Sincerely

Werner Rissiek
Siemens Nixdorf / Cadlab
Received on Wed Oct 13 05:51:56 1993