AW: Question Vinh/l+, Vinh/l-

Hello Bob:

The Vinh+, Vinh-, Vinl+ and Vinh- definition is a litle bit confusing for
me. We take the Vinh+ and the Vinl+ values, which have been evaluated under
max conditions and the Vinh- and Vinl- values, which have been evaluated
under min conditions and put these data in the typ colum of the IBIS file.
Why we don't put these data in the max and min colums?
Yes I know there must be data in the typ colum but nevertheless it stays
confusing for me.

Best regards

Bernhard

> ----------
> Von: Bob Ross[SMTP:bob_ross@mentorg.com]
> Gesendet: Mittwoch, 16. Juni 1999 02:52
> An: Sporrer cad52
> Cc: ibis@eda.org
> Betreff: Re: Question Vinh/l+, Vinh/l-
>
> Hello Christian:
>
> Some specifications for Schmitt trigger (or hysteresis) inputs
> give values in terms of Vt+ for the high threshold value and
> Vt- for a low threshold value.
>
> One old example is the 74XXX132 series of devices.
>
> The Texas Instruments TTL Logic data book gives min, typ and
> max Vt+ and min, typ, and max Vt- values and defines them as
> Positive-Going Threshold Voltage Vt+ and Negative-Going Threshold
> Voltage Vt-
>
> From BIRD39 the following diagram illustrates how the hysteresis
> subparameters are defined:
>
> ^
> O | +-------+----<----+--------+------------
> U | ! ! ! !
> T | ! ! ! !
> P | ! ! ! !
> U | ! ! ! !
> T | ! ! ! !
> | v v ^ ^
> V | ! ! ! !
> O | ! ! ! !
> L | ! ! ! !
> T | ! ! ! !
> T | ! ! ! !
> A | ! ! ! !
> G | ! ! ! !
> E | -----------+-------+---->----+--------+
> |_____________________________________________________________>
> Vinl- Vinl+ Vinh- Vinh+
> INPUT VOLTAGE
>
>
> IBIS Version 3.2 relates the Vt+ and Vt- min and max values that may
> appear in data books as follows:
>
> | Vinh+ Hysteresis threshold high max Vt+
> | Vinh- Hysteresis threshold high min Vt+
> | Vinl+ Hysteresis threshold low max Vt-
> | Vinl- Hysteresis threshold low min Vt-
>
>
> Whether or not the data book uses the Vt+ and Vt- terminology, the
> hysteresis or Schmitt trigger inputs should be entered consistent
> with the figure above.
>
> Best Regards,
> Bob Ross
> Mentor Graphics
>
>
> Sporrer cad52 wrote:
> >
> > Hi,
> >
> > I am from Infineon Technolgies AG, Munich (former Siemens
> > Semiconductor) and responsible for the generation of IBIS
> > models for our IO-cell libraries.
> >
> > For IBIS 3.x I have a problem with the meaning of Vinh+,
> > Vinh-, Vinl+ and Vinl- subparameters inside the
> > [Model Spec] Keyword.
> > What is the difference between Vinh/l+ and Vinh/l- ?
> > What is the meaning of Vt+/Vt- ?
> >
> > Process, temperature and voltage variation is considered
> > in the typ, min and max columns. But what kind of
> > variation must be done to get different Vin(h+-)/(l+-)
> > values?
> >
> > I hope somebody can help me.
> >
> > Thanks Christian.
> >
> > Christian Sporrer
> > Infineon Technologies Munich
> > Email: Christian.Sporrer@infineon.com
> > Tel: +49 89 234 24069
> > Fax: +49 89 234 28555
>
Received on Wed Jun 16 01:09:34 1999