Subject: drlc model

From: Alex Hilbers <[email-masked]>
Date: Thu, 28 Sep 2000 10:18:14 +0200 (MET DST)

Dear Ibisians,

although ibis is meant to be used for IC buffer modelling:

how about the simple diodes, resistors, capacitors and inductors?

Is it possible to model such a simple component with ibis?

Regards

Alex

---

From: Peled Sarit <[email-masked]>
Date: Thu, 28 Sep 2000 14:03:47 +0300 (IDT)

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
[email-masked]

---

From: Mike LaBonte <[email-masked]>
Date: Thu, 28 Sep 2000 12:41:19 -0400

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