Re: question on SPICE to IBIS translation

Binshen Meng,

You should use rise and fall times that are consistent with the on-chip
rise and fall times that the driver sees at its input. These numbers will
depend on the silicon technology, the circuit driving the driver's input,
and the loading (metal and gates) on this circuit. The manufacturer will
not provide this information on a datasheet. You could call them up if you
were really serious.

What I would do is see how sensitive your driver is to input rise and fall
time. Vary the input between 100 ps and 500 ps and see if you notice
anything more than a phase shift in your driver's output waveform. Try two
or three different loads, including a system-like load. If things look
pretty much the same, then you're probably safe using any number in this
range

Greg Edlund
Advisory Engineer, Critical Net Analysis
IBM
3650 Hwy. 52 N, Dept. HDC
Rochester, MN 55901
gedlund@us.ibm.com

Binshen Meng <bmeng@pluris.com> on 02/24/2000 01:31:16 PM

To: "'ibis-users@eda.org'" <ibis-users@eda.org>
cc:
Subject: question on SPICE to IBIS translation

I have a question on generating V-T curves from SPICE models. How should I
determine the slew rate that is used for the pulse stimulus in the
transient
simulation in HSPICE ( tr and tf in the statement: PULSE v1 v2 td tr tf
pw per )? I have seen many sample simulations using difference slew rates
(or transient rising or falling edges). Do component manufacturers provide
this information in their data sheets? If not, what is the rule of thumb in
determining it? Should that be generally very fast?....

Thanks for your help

Binshen Meng
Pluris, Inc
408-861-4132
Received on Fri Feb 25 00:47:04 2000