Re: [IBIS-Users] way to extract rising and falling waveform in differential cells

Hello Andy,

 That means we can't make IBIS model that work at 1ghz. I think we can
make IBIS models at such high frequency. Now I put both rising and
falling database in my model and it is parsed by golden parser without
any problem but still result are not good at 622Mhz.
  Is this also problem from simulator. I am using eldo (AMS CADENCE)for
validation.

Regards
Akhilesh

Andrew Ingraham wrote:

> Akhilesh,
>
> In the example you gave earlier, the simulation was at 250 MHz (2 ns
> high and 2 ns low) and the waveform had just about reached the other
> state when it was being switched again. Attempting to simulate this
> much faster (622 MHz or 1 GHz), with IBIS, is probably doomed to
> failure because of IBIS's limitations. This is sometimes known as
> "over-clocking" the IBIS model, because the model hasn't reached the
> other state yet when it is being clocked again in the other
> direction. Some simulators handle this situation very poorly, so
> you could see very poor IBIS vs. SPICE correlation at such
> faster frequencies.
>
> Regards,
> Andy
>
>

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Received on Sun Dec 19 07:39:52 2004