Re: drlc model

IBIS is not really intended for passive discrete parts like
resistors, capacitors, and inductors. That said, it is possible
to model them in IBIS. But to do so requires a [Series Pin Mapping]
section and a [Model] with Model_type Series. The example sent
by Peled isn't exactly an IBIS file. For example, it has an [RSeries]
item which is not described at all in the IBIS specification. It
is possible that this file will work with the ICX simulator, however.
I am not certain of what limitations a standard IBIS Series model has
that would actually require non-IBIS extensions, at least for simple
parts.

This does raise an interesting point about IBIS: it does not, or did
not at one time, model ALL of the parts used in electronic designs.
So simulators were forced to implement a separate model format for
the other parts. Some simulators use proprietary "extended IBIS" files.
However, we must be careful not to disseminate these as standard IBIS
files. Since handling of these other part types is important to end
users, maybe the scope of IBIS specification should be expanded to
standardize them as well?

Mike LaBonte
Cadence Design Systems

Peled Sarit wrote:
>
> Hi
>
> YES . You can write an invented model which is not based on measurments,
> but rather is based on the component's given parameters .
> As an example : this file is an IBIS file for a 50 ohm resistor, it comes
> as part of the default IBIS files supplied with the ICX simulator (by
> Mentor Graphics).
>
> |****************************************************************************
> |
> [IBIS Ver] 2.1
> [File name] icxresistor.ibs
> [File Rev] 0.0
> [Date] 10/24/97
> [Source] None.
> [Notes] Default model for resistor.
> [Disclaimer] This information is for modeling purposes only, and
> is not guaranteed.
> |
> |***************************************************************************
> |
> [Component] icxresistor
> [Manufacturer] UNKNOWN
> [Package]
> | typ min max
> R_pkg 0 NA NA
> L_pkg 5.0nH NA NA
> C_pkg 2.0pF NA NA
> |
> [Pin] signal_name model_name R_pin L_pin C_pin
> 1 UNKNOWN resistor_50 NA NA NA
> 2 UNKNOWN resistor_50 NA NA NA
> |
> |***************************************************************************
> |
> [Model] resistor_50
> Model_type Terminator
> Polarity Non-Inverting
> C_comp 0 NA NA
> [Voltage range] 0 NA NA
> [Pullup Reference] 5 NA NA
> [Pulldown Reference] 0 NA NA
> [Power_clamp Reference] 5 NA NA
> [Gnd_clamp Reference] 0 NA NA
> [RSeries] 50 NA NA
> |
> |***************************************************************************
> |
> [End]
>
> Of course, you can always make a more accurate model by measuring or
> simulating additional parameters (such as L and C for the resistor
> package).
>
> best regards ,
>
> Sarit Peled
> speled@t2.technion.ac.il
 
Received on Thu Sep 28 09:36:22 2000