Diode Modeling in SPICE

Hello IBIS model makers !

   I have a 5V CMOS I/O tristate-able buffer I'm trying to model. The IBIS
curves generated by s2ibis2 are a very good match
   to measured data between 0.7v up to about 5.9v. But between -5V to 0.7v
and 5.9v to 10v the curves deviate quite a bit.
   I've disabled the parasitic diodes in the nmos and pmos device models (
IS=0 ) and added n+ and p+ parasitic diodes to the
   netlist. I've been playing with the n+ and p+ diode model (level 3)
parameters ( n, js, ivb, area, pj ) trying to match SPICE
   results to measured data with limited success.

   Are there any suggestions for other model parameters to tweek, or maybe
there is something going on with the s2ibis2 SPICE
   sim limits/parameters I'm not aware of ?
 
  Thanks,
  The time you spend helping me out is greatly appreciated !

   Silvia Montoya
  email : silvia.montoya@actel.com
Received on Thu May 13 16:56:36 1999