Subject: Help on V/T Tables

From: "Charles Hymowitz" <[email-masked]>
Date: Fri, 2 Oct 1998 14:01:54 -0800

To IBIS users

We are interested in implementing the V/T tables Ramp feature in the
free IBIS to SPICE converter that we have posted. Right now only the
simple dV/dT numbers are accesible from the Converter for the
resulting SPICE model. I assume that the tables are there because a
simple slew rate limiting model is not sufficient.

It seems that this is a two part problem.
1)  What should the converter do with the V/T table data and 
2) how can a SPICE model use the data to implement the 
characteristic.

Is there any information anyone can provide me with that details how
the V/T table could be implemented in a SPICE model?

Please note that I have asked this question of a few people 
and the answer I get is that it is posible using proprietary 
SPICE model primitives. It seems to me the end users would benefit 
greatly from a SPICE-like topology and primitive model set that 
handles the V/T table feature of IBIS.

BTW There exists a public domain standard for adding C code 
subroutines to SPICE as new model primitives. Its called XSPICE and 
its used by 7 different SPICE vendors. C source code done in XSPICE 
will run on these seven vendors SPICE programs and anyone else who 
adopts XSPICE extensions to SPICE. XSPICE is from the Georgia 
Institute of Technology and is freely available. XSPICE already has 
an extended SPICE primitive set including 40 extra SPICE primtives 
like slew rate limiter, table model, laplace model, VCOs, etc.

Is there anyone out there who can supply the subcircuit topology and 
description of the required new SPICE primitives? We would gladly add 
this capability to the free converter.

Charles Hymowitz - V.P. Prod. Dev.
Intusoft
email: [email-masked], CompuServe: [email-masked]
Web: http://www.intusoft.com
Tel. (310) 833-0710, Fax (310) 833-9658
P.O. Box 710, San Pedro CA. 90733-0710

Please visit our web site @ http://www.intusoft.com for more information
and lots of SPICE goodies.