Re: Proposed Golden IBIS Parser checks

Kellee Crisafulli wrote:
> At 11:43 AM 11/4/98 -0700, D. C. Sessions wrote:
> >Matthew Flora wrote:
> >> Proposed enhancements:

> >> 3) For non-ECL models, shouldn't the zero current voltage for the Typ, Min,
> >> and Max columns in the Pullup or Pulldown V/I tables be the same (say
> >> within a microvolt)? I suggest that a warning be generated if they are
> >> not.
> >Lots of technologies have zero-current intercepts inside of their
> >rails. ECL is only one of them; perhaps you've heard of TTL?

> I think Matt is asking that the zero current intercept be the same for
> typ,min,max not that it be 0.

Still wouldn't work. TTL (to pick one) intercepts when the
forward current through the base-collector junction equals
the pulldown current through the collector-emitter path.
This depends on the forward voltage of the base-emitter
junction, the beta of the transistor, and the forward
voltage of the collector-base junction as well as the
predriver current to the transistor base node (also variable).
The first three are dependent on process and temperature, and
the last is also dependent on supply voltage. IOW, the
open-circuit Vol is going to be all over the place.

-- 
D. C. Sessions
dc.sessions@vlsi.com