[ibis-macro] Re: Analog BIRD comparison

  • From: Feras Al-Hawari <feras@xxxxxxxxxxx>
  • To: "Arpad_Muranyi@xxxxxxxxxx" <Arpad_Muranyi@xxxxxxxxxx>, IBIS-ATM <ibis-macro@xxxxxxxxxxxxx>
  • Date: Wed, 18 Jan 2012 09:08:05 -0800

Hello Arpad,

In our proposal we are referencing an S-parameter (that represents an active 
linear device) from an External Model section. An External Model block was 
introduced in IBIS to model analog I/O buffers. Hence based on our proposal we 
are adding new constructs in the appropriate container and we are not 
intermixing different blocks together. AMI should remain simple and should only 
contain algorithmic models (dlls). While any advanced constructs that intend to 
model analog I/O buffers should be done under the External Model section in an 
simple and generic way. Touchstone is very widespread and it can be wrapped in 
a SPICE-like subckt and then used in an External Model. Or as we are proposing 
it can be called directly from an External Model without wrapping to make 
things easier to the user. 

Best regards,

Feras Al-Hawari
Cadence Design Systems

-----Original Message-----
From: ibis-macro-bounce@xxxxxxxxxxxxx [mailto:ibis-macro-bounce@xxxxxxxxxxxxx] 
On Behalf Of Muranyi, Arpad
Sent: Tuesday, January 17, 2012 8:06 PM
To: IBIS-ATM
Subject: [ibis-macro] Re: Analog BIRD comparison

Ambrish,

Thanks for your comments.  I think this might be
somewhat of a terminology issue.  I made that
comment based on the view that an S-parameter
block, if considered a circuit element, is connected
in a predetermined way, as described in BIRD 144, or
in Walter's proposal.  To me both of these are
predefined circuit topologies.

One might argue that the content of an S-parameter
can represent practically any circuit topology,
therefore BIRD 144 odes not describe a predefined
circuit topology, but that argument would also apply
to the S-parameter portion of Walter's proposal.

I am just trying to say that we should try to be
consistent.

We discussed two forms of Walter's "hard coded" circuits
in today's ATM meeting.  One that contains a predefined
RC circuit topology, and another that is replacing that 
with an S-parameter block.  Are you saying that the latter
is not predefined then, and consequently are you OK with
Walter's proposal as long as it makes use of S-parameters
only?

To me it seems that whether it is Walter's proposal or
BIRD 144, the direct connection of the S-parameter block
is pretty much the same in both proposals.  If we oppose
one, then we should also oppose the other.

Thanks,

Arpad
===========================================================


-----Original Message-----
From: ibis-macro-bounce@xxxxxxxxxxxxx [mailto:ibis-macro-bounce@xxxxxxxxxxxxx] 
On Behalf Of Ambrish Varma
Sent: Tuesday, January 17, 2012 6:21 PM
To: IBIS-ATM
Subject: [ibis-macro] Analog BIRD comparison

Hi Arpad,
Thanks for putting these slides together. I would like to clarify something 
that you mentioned during the ATM call and also point out on slide 3 of the 
Analog BIRD comparison pdf. BIRD 144.1 does not describe a 'predefined circuit 
topology (that) eliminates the need for an IBIS-ISS subcircuit'. Only the 
latter part of the statement is accurate - it eliminates the need for an 
IBIS-ISS subcircuit when an external tstone file is being pointed to. It simply 
allows the model maker to directly refer the tstone file from the external 
model keyword. There is no attempt to pre-define a circuit or present a canned 
solution for any analog circuit. 

Another aspect of BIRD 144 is to allow user defined corners for analog models 
(described with a tstone file) for more than the allowed 3 corners *without* 
the need of an AMI parameter file. This functionality would keep the analog 
model entirely within the IBIS file and away from the AMI part of the 
specification. 

Thanks and Regards,
Ambrish. 

Ps: I changed the subject line to better reflect the topic of discussion.
 
Ambrish Varma   |  Member of Consulting Staff
P: 978.262.6431   www.cadence.com
 
 
 
 
 

-----Original Message-----
From: ibis-macro-bounce@xxxxxxxxxxxxx [mailto:ibis-macro-bounce@xxxxxxxxxxxxx] 
On Behalf Of Muranyi, Arpad
Sent: Tuesday, January 17, 2012 2:23 PM
To: IBIS-ATM
Subject: [ibis-macro] Re: IBIS-ATM teleconference - Agenda for 1/17/2011

I prepared a couple of slides to aid our
discussion today.

These slides are an attempt to summarize the
various arguments (pro/con) with the goal of
helping our decision process at the end.  I 
intend to keep adding more to these slides as
we go with our discussions.

Thanks,

Arpad
================================================

-----Original Message-----
From: ibis-macro-bounce@xxxxxxxxxxxxx [mailto:ibis-macro-bounce@xxxxxxxxxxxxx] 
On Behalf Of Muranyi, Arpad
Sent: Tuesday, January 17, 2012 10:58 AM
To: IBIS-ATM
Subject: [ibis-macro] IBIS-ATM teleconference - Agenda for 1/17/2011

Time:  January 17, 2012  Noon  US Pacific Time
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Meeting schedule for the next few weeks:
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We need a volunteer to take minutes today.


Agenda
======

1) Opens
2) Call for any related patent disclosures
3) Review of ARs:


Walter:  Submit updated BIRD 123 to Open Forum
         - done (This is 123.2)

Arpad:   Submit Usage Out correction BIRD draft to Open Forum
         - done

Any other AR-s?


Old ARs:

Arpad:  Review the documentation (annotation) in the macro libraries.
        - deferred until a demand arises or we have nothing else to do


4)  Analog BIRDs discussion
    BIRD 122                                                 (Walter)
    - working documents: ISS_Buffer_BIRD.doc (May 17, 2011)
                         ISS_Package_BIRD_RevA.doc (May 27, 2011)

    BIRD 116, 117, 118, 129 for buffer modeling               (Arpad)
    BIRD 125  for package modeling                            (Arpad)

    BIRD 144, 145                                           (Cadence)


5)  BIRD 121.1, data management parameters (file support)    (Walter)
    - discussion, questions, comments?


6)  BIRD 124.1, dependency table                             (Walter)
    - questions, comments?


7)  Info, Out, InOut BIRD                                     (Arpad)
    - latest wording includes "in order to be compliant with this
      specification, Model_Specific parameters ... must not ...",
      and omits the word "simulation" so it's meaning doesn't have
      to be defined
    - any comments, questions on this draft?


8)  "Resolution"                                             (Walter)
    - do not include 5.0 rule descriptions in the 5.1 specification


Thanks,

Arpad
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