Subject: V/I table checking

From: [email-masked] ( Bob Ross)
Date: Thu, 17 Mar 94 13:56:59 PST

To IBIS Committee and Will

Thanks for your response on Monotonicity.  I goofed in confusing the
Monotonicity discussion with the checking discussion because I
read INCORRECTLY into 4) as "any table entry ..." instead of "any table ..."
So, one gooney bird award to me.  One member of the "God-like assembly
that can make no error" can make errors.

I think the discussion should continue on the checker modification with 
still the possibility of rapid agreement.

If this proposal is adopted, it would apply to just IBIS Version1.1.  The
polarity rules do not comply with proposed IBIS extensions BIRDS 3 and 4
for ECL type devices.  For ECL type devices, the polarities of both the
Pullup and Pulldown tables will go in the same (decreasing) direction 
because BOTH tables are tabulated referenced to Vcc using
       Vtable = Vcc - Vout.  
I am sure this will become another area of confusion, justifying a test. 

I have a problem at this time with test 5) checking for equal currents at
Vmin and Vmax and flagging it as an error if they are equal.  This may
be an acceptable condition if the currents are 0 ma.  Also it may be
possible to approximate a constant current source or sink with an "ideal" 
current source using a constant clamping current, although I have not
thought out all of the implications of doing this.

In general, I can accept the V/I table checking proposal but prefer it to
be modified to allow Equal current values.

Bob Ross
Interconnectix, Inc.