RE: dual curve issue for input pad

Weber Chuang wrote:

> I am currently involved in the design of a I/O pad and building
IBIS
> for it, but I am facing some troubles, my I/O
> pad has dual I/V curves while in input mode, that is, the I/V curves
for
> rising input and falling input are
> different. IBIS seems to not supporting this kind of design, and
s2ibis2
> will not generate correct model for this. Is
> there any workaround? Any comment is welcome.

Are you talking about a hysteresis-like feedback characteristic, such as
a bus-hold circuit?

If so, IBIS doesn't do it. Both because it doesn't handle input I/V
curves that change, and because bus-hold input curves are non-monotonic
which can create problems for the simulator.

(Someone correct me if I'm wrong or if version 3 changes this.)

Regards,
Andy Ingraham

 
Received on Wed Feb 18 08:44:53 1998