[ibis-macro] Re: Analog Buffer model - the User's viewpoint

  • From: Ambrish Varma <ambrishv@xxxxxxxxxxx>
  • To: IBIS-ATM <ibis-macro@xxxxxxxxxxxxx>
  • Date: Fri, 20 Jan 2012 13:16:47 -0800

We are not suggesting that BIRD 144 will replace BIRD 116. So if BIRD 116 & 
dependency tables can fulfill your requirement, then great. Look at BIRD 144 as 
a quick way of bypassing the requirement of having a subcct for the case when 
the user wants to refer to a tstone file.
Hope I read your issue correctly.


Ambrish Varma   |  Member of Consulting Staff

P: 978.262.6431   www.cadence.com<http://www.cadence.com>

From: ibis-macro-bounce@xxxxxxxxxxxxx [mailto:ibis-macro-bounce@xxxxxxxxxxxxx] 
On Behalf Of Todd Westerhoff
Sent: Friday, January 20, 2012 4:03 PM
Subject: [ibis-macro] Analog Buffer model - the User's viewpoint


One of my colleagues here brought up a good point today - how the end-user 
interacts with the model.

How do we expect that the user wants to interact with an IBIS-AMI model?  
Specifically, how would they want to set up and run simulations?  The answer, 
in SiSoft's opinion, is to specify values for control parameters that 
correspond as closely to the actual hardware as possible.  Obviously a deep and 
broad subject, of which I want to comment only on one small slice: how it 
relates to analog modeling.

Let's assume we have a model where the output impedance (static impedance, as 
Scott defined it) varies considerably depending on the TX output swing setting. 
 We expect that the user wants controls that lets them set the output swing and 
EQ settings in a way where the mapping to hardware settings is obvious, with 
the model/simulator figuring out to configure the details of the model.  
Chances are, the analog model to be used will change as a function of the 
output swing and EQ settings selected.  If we're using subcircuit (as proposed 
by BIRD 116) or Touchstone (as proposed by BIRD 144) methods, either the 
equivalent circuit parameters (BIRD 116), or the Touchstone file selection 
(BIRD 144) will have to change, depending on how the user sets the input 
controls.  I believe BIRD 116 & dependency tables can fulfill this requirement, 
but I'm not sure that BIRD 144 (as currently proposed) can do this.



Todd Westerhoff
VP, Software Products
6 Clock Tower Place, Suite 250
Maynard, MA 01754
(978) 461-0449 x24

"It doesn't matter what you've heard
  Impossible is not a word
  It's just a reason
  For someone not to try"

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