RE: IBIS component generation, PECL differential inputs, analog I/O pins, Vmeas, Cref, Rref, Vref

Hi chang,
        
        Included inline comments. Please someone correct me, if I made
        any mistake.

> Hello, I am using s2ibis2 and HSPICE netlists to generate IBIS files. I
> am using s2ibis2 to first generate IBIS models for the inidividual
> "types" of pins, and then cutting and pasting the [Model] portion of the
> individual IBIS pin models into a larger "main" IBIS file which
> describes the entire component. This saves having to set up s2ibis2 for
> generating the entire component all at once. Once created, I can use
> and reuse IBIS pin models for pins on the component that are identical
> in nature. Is there any problem with the IBIS model generation scheme
> I've outlined above? I would especially like to hear from other people
> who have worked with s2ibis2 and SPICE to create their IBIS models.

        This is correct way of doing.

>
> Secondly, I am now faced with how to setup both the s2ibis2 *.s2i file
> and the IBIS file for some PECL (Pseudo-ECL) differential inputs. Has
> anyone had to generate IBIS models for pins that are both differential
> and Pseudo-ECL(or ECL) before? How does s2ibis2 handle the [Diff pin]
> Keyword, and associated pin list section? In the s2ibis2 manual, it says
> that no processing is actually performed on the [Diff pin] list. Does
> this mean that I could create a single ECL input pin first using
> s2ibis2, include the [Model] section of the single ECL input IBIS file
> into a 'main' IBIS file for a component, connect the model name to
> appropriate pins on the component, and then add the [Diff pin] pin list
> later in the actual 'main' IBIS file for the component?

        For PECL & ECL:--

        In s2i define [Pullup Reference] and [Pulldown Reference] to VCC.
        [Model type] to be of Ouput_ECL or Input_ECL. Rest of the s2i is
        simillar (Voltage Range not required). The vout variation for
        pullup and pulldown from VCC to VCC-2.2 . In IBIS tablular format
        you refer to VCC. I encountered a problem in using s2ibis2 for
        PECL (5V) device. You can edit the *.spi files set up by s2ibis2
        and use [iterate] option to process SPICE input files in accordance
        with specs. I also found problem in tabulating IBIS file by reading *.out
        files.

        [Diff pin] is not processed by s2ibis2. It's right to add [Diff]
        section at the end.

>
> Thirdly, how are analog I/O pins treated in IBIS and s2ibis2? How would
> I setup an analog I/O pin in s2ibis2 and IBIS?

        Scope of IBIS is restricted to analog behaviour of Digital ICS.
        I am not sure what you really mean by analog I/O pin ?.
>
> And finally, are the Vmeas, Cref, Rref, Vref parameters used for
> anything in s2ibis2, or in IBIS files? (are they actually processed? or
> are they just for reference)

        No they are not used. This information is reference
        for IBIS based simulators.
>

..srinu

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Received on Fri Jun 13 00:00:11 1997