Subject: BIRD6 comment

From: [email-masked] ( Bob Ross)
Date: Fri, 21 Jan 94 16:08:58 PST

Hello again IBIS flock:

Thanks Kellee for your comments, I agree with your "vdiff" terminology
change, or whatever people feel is best.  Also, you raised a good
point regarding differential skew.  For example, the National
DS3695A/DS3695AT/DS3696A/DS3696AT Multipoint RS485/RS422 Tranceivers
in the Interface Databook specify this and show a waveform.  Another
column could be added for this in [Diff_pin].

I think using the POLARITY in the model instead of the sign of "vdiff"
is a good alternative.  In that way the polarity of of "vdiff" could be
reserved more appropriately for a hypothetical differential device with 
differential hysterisis (although I have not found such a device).

In doing Bird6, I had a problem in choosing whether one [Model] could
be used or two [Model]s were required, one for Positve and one for Negative
Polarities.  In its present form, two [Model]s (even different models -
and I have seen cases where complementary outputs in some latches differ) can
be used if necessary, but one [Model] is sufficient.  Your POLARITY 
specification method would work for both cases.

Bob Ross
Interconnectix, Inc.