Re: [IBIS-Users] s2ibis2 problem with 3-stateable OD drivers

Subject: Re: [IBIS-Users] s2ibis2 problem with 3-stateable OD drivers
From: Fred Balistreri (fred@apsimtech.com)
Date: Tue Nov 26 2002 - 10:14:57 PST

Hello Henrik, your information below says Open_sink not Open_drain.
No matter, you may want to try I/O_open_drain (or sink) as the proper
pin type.

Best Regards,

"Henrik G. Madsen" wrote:
>
> To me it seems that s2ibis2 do not support generation of open-drain models with tri-state outputs properly.
> I'm using the Windows version, but I believe that the issue is of general nature.
>
> ********** From .s2i file
> [Pin]
> pad pad pad osoc2_od
> -> D EN
> D D D input
> EN EN EN enable
> VDD VDD VDD POWER
> VSS VSS VSS GND
>
> [Model] osoc2_od
> [Model type] Open_sink
> [Polarity] Non-Inverting
> [Enable] Active-low
> *************
>
> The above will not generate the correct VI tables.
>
> By using the above info, s2ibis2 will generate spice simulations for
> 1) 'Pulldown curve'
> 2) 'Pulldown curve with output disabled'
> but no 'Ground clamp' simulation.
> I assume it then creates the IBIS PULLDOWN curve by subtraction the second curve from the first one (only for negative voltages).
> The resulting IBIS model only has one VI curve, the modified PULLDOWN where the clamping has been subtracted. But it does not add the missing current by adding a 'Ground Clamp' curve.
>
> It seems that a correct result only can be obtained by removing the enable signal and run s2ibis2 with that, Or create the missing 'Ground Clamp' curve manually.
>
> Can it be true that s2ibis2 do not support OD-drivers with enable signal?
>
> _____________________________________
> Henrik G Madsen
> Sr. HW Engineer
> Vitesse Semiconductor Corporation A/S
> Ethernet Products Division
> Hoerkaer 16, DK-2730 Herlev, DENMARK
> Direct: +45 4485 5920
> Phone: +45 4485 5900, Fax: +45 4485 5901
> mail: hgm@vitesse.com
> web: http://www.vitesse.com
> _____________________________________
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-- 
Fred Balistreri
fred@apsimtech.com

http://www.apsimtech.com
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