Re: Proposed Golden IBIS Parser checks

D. C.,

>> Proposed enhancements:
>
>> 2) Generate at least a warning if the Pullup or Pulldown V/I table
>> indicates that current is always flowing in one direction. In other
>> words, the V/I table does not have an entry with zero current or, by
>> interpolation, the current is never zero in the range of the voltages
>> listed.
>>
>> I think a warning should be generated even if the current would be zero
>> when extrapolated to a voltage beyond those listed in the table because
>> I believe that V/I tables should be complete and should not force a
>> simulator to guess values and, to me, extrapolation beyond the voltages
> listed in the table is a guess.
>
>If I understand you correctly, you would insist that the tables
>go at least to the zero-current intercept point. Thus, for an
>1.5v device with a weak pullup to 5.0v you'd have the tables go
>at least to 5v so as to catch the intercept?

In a word, yes. If you have a 1.5v buffer which is active all the way up to
5v, then it's behavior needs to be described. I thought V/I tables are
supposed to show the behavior of the device in its active region, and perhaps
a bit beyond its active region. I thought that is why the spec suggests
generally spanning the voltages between -Vcc and 2Vcc.

>> 4) Related to a topic recently discussed on the reflector, I suggest that
>> an error be generated if a differential pin (a pin referenced in the
>> [Diff pin] section) is connected to one of the reserved models (POWER,
>> GND, or NC).
>
>This would barf on RS-423

I am not familiar with RS-423. Does it have one or more pins whose voltage is
to be taken differentially to POWER or GND?

Cheers,
Matt
Received on Wed Nov 4 12:45:43 1998