Re: Non-monotonicity in IBIS models

Greg,

non-monotonic behavior which is outside of the normal
operating range of the device, and be smoothed to
eliminate the behavior. This will have absolutely no
effect on simulation ... as long as the signalling range
does not enter this region.

regards,

scott

--
Scott McMorrow
Principal Engineer
SiQual, Signal Quality Engineering
18735 SW Boones Ferry Road
Tualatin, OR  97062-3090
(503) 885-1231
http://www.siqual.com
Greg Haynes wrote:
> I'm interested in the discussion about
> non-monotonicity of I/V curves.  This seems
> to be very common in our parts, and is definitely
> real, that is, it shows up in the HSPICE simulation
> and in the physical part measured on a curve tracer.
>
> One example is an LVDS receiver that has a spike
> in the current at about 1 volt above VDD.  This
> is not just an artifact of subtracting the ground
> clamp current from the pulldown current.
> (Incidentally, I can't get a good explanation
> for this behavior.  The designers of the parts
> don't simulate with voltage outside the rails,
> and they typically tell me that the SPICE models
> may not be any good in this region anyway!)
>
> I don't know what I should do in this case.  I
> don't know which tools customers may want to use
> so I don't know if this will really be a problem
> for them.  Are there any guidelines about how to
> "smooth out the non-monotonicity"?  And if I do
> change the data, how can tools give accurate results
> with IBIS models that now do not reflect the
> physical part?
>
> --
> Greg Haynes               haynes@utmc.aeroflex.com
> Aeroflex UTMC Microelectronic Systems
> 4350 Centennial Blvd           phone: 719 594-8197
> Colorado Springs, CO 80907       fax: 719 594-5541