Re: [IBIS-Users] ibischk4

Of course the Ramp data depends on the driver strength!

I don't know what I was thinking yesterday ... I apparently wasn't.
(Momentary brain fart. Nevermind!)

I have had IBIS device models where the dV part of the [Ramp] data was
nowhere near to agreeing with the I-V data.

It is also suspicious when a vendor gives you models with different I-V
tables (or when they update a model and it has new I-V data), but precisely
the same Ramp data. Obviously they took shortcuts, and the whole model is
suspect.

I'm surprised that this isn't verified by ibischk. It should be.

Katja, I would be careful about thinking that the ramp edge linear, all the
way from 0 to 100%. It is probably not a bad assumption between 20 and 80%,
but many waveforms have much lower slopes before 20% or after 80% ...
especially beyond 10% and 90%. The first half cycle of a cosine wave isn't
a bad approximation to some real signals into resistive loads.

You might get by with a piecewise linear approximation where the 0-20% and
80-100% portions have much lower dv/dt, perhaps a third of that between 20
and 80%.

Regards,
Andy

|------------------------------------------------------------------
|For help or to subscribe/unsubscribe, email majordomo@eda.org
|with just the appropriate command message(s) in the body:
|
| help
| subscribe ibis <optional e-mail address, if different>
| subscribe ibis-users <optional e-mail address, if different>
| unsubscribe ibis <optional e-mail address, if different>
| unsubscribe ibis-users <optional e-mail address, if different>
|
|or email a written request to ibis-request@eda.org.
|
|IBIS reflector archives exist under:
|
| http://www.eda.org/pub/ibis/email_archive/ Recent
| http://www.eda.org/pub/ibis/users_archive/ Recent
| http://www.eda.org/pub/ibis/email/ E-mail since 1993
Received on Thu Nov 4 05:45:14 2004