Re: rise & fall waveforms

> My question is about rising and falling waveforms.
> In order to generate these curves with s2ibis2, you have to specify
> certain parameters for the test fixture. This makes it relevent to
> that specific fixture. So, should these curves be generated
> only when making actual measurements to produce an IBIS model,
> or should I generate them using s2ibis2 ?

They are meaningful whether generated by SPICE or measured data.
Test fixture = test load (applied to the SPICE model, or to the
real DUT via test fixtures.)

> If I should generate them with the automatic conversion,
> what is a common fixture resistance?

For ordinary TTL/CMOS outputs, try 50 or 100 ohms to GND (for rising)
and to POWER (for falling). Also a few other resistances, up to
1000 ohms or so. Do the same when you generate measured data.

Regards,
Andy
 
Received on Wed Jul 23 19:34:38 1997