Re: Question to IBIS Reflector

Scott:

From a bench measurement point of view, it's almost impossible to
measure rise/fall on a die(wafer). Measuring Rise/Fall on a packaged device
takes into account the C_comp effect as well.

I believe this parameter measurements were defined by SPICE users where it's easy
to isolate package effects.

Regards,
Syed
National Semiconductor Corp.

> From owner-ibis@vhdl.vhdl.org Wed Oct 30 11:42:53 1996
> Date: Wed, 30 Oct 96 12:35:14 PPE
> From: scotts@actel.com (Scott Schlachter)
> To: ibis@vhdl.org
> Subject: Question to IBIS Reflector
> Content-Length: 641
>
> IBIS folk:
>
> I am curious how one does rise and fall time measurements
> using packaged parts. The spec calls for these ramps to be measured
> on I/Os with no loading, but this implies wafer-level measurements
> which are less than ideal from a noise standpoint. One can use a
> high-impedance probe on packaged parts but then one gets a few pF
> and a few nH of LC network. In programmable logic it is almost
> imperative that a tester be used, as the I/Os must be programmed
> into their appropriate modes.
>
> My guess is that this will cause little effect on the
> rise and fall times, but is this correct? Is this something that
> really must be SPICEd?
>
>
Received on Wed Oct 30 12:30:16 1996