[ibis-macro] Re: AMI-init should pass modified IR to getwave....

  • From: Taranjit Kukal <kukal@xxxxxxxxxxx>
  • To: "'twesterh@xxxxxxxxxx'" <twesterh@xxxxxxxxxx>, "'ibis-macro@xxxxxxxxxxxxx'" <ibis-macro@xxxxxxxxxxxxx>
  • Date: Thu, 14 Jun 2012 20:07:29 +0530

Hi Todd,
Your description of RDL is correct.
Rx is at the buffer i/p so RDL essentially becomes additional channel.


From: Todd Westerhoff [mailto:twesterh@xxxxxxxxxx]
Sent: Thursday, June 14, 2012 07:09 PM
To: 'IBIS-ATM' <ibis-macro@xxxxxxxxxxxxx>
Subject: [ibis-macro] Re: AMI-init should pass modified IR to getwave....


When you say “On chip RDL”, are you specifically talking about the interconnect 
between the die pad and the buffer itself?  Where is the receiver termination 
physically taking place?


Todd Westerhoff
VP, Software Products

Signal Integrity Software Inc. • www.sisoft.com<http://www.sisoft.com/>
6 Clock Tower Place • Suite 250 • Maynard, MA 01754
(978) 461-0449 x24  •  twesterh@xxxxxxxxxx<mailto:twesterh@xxxxxxxxxx>

“I want to live like that ”
                                             -Sidewalk Prophets

From: ibis-macro-bounce@xxxxxxxxxxxxx [mailto:ibis-macro-bounce@xxxxxxxxxxxxx] 
On Behalf Of Taranjit Kukal
Sent: Thursday, June 14, 2012 2:04 AM
Subject: [ibis-macro] AMI-init should pass modified IR to getwave....

Hi All,
When I was implementing AMI model, I found a situation where it was important 
that Rx ami_init needed to pass modified-IR to getwave function.
Reason was that Chip-RDL-routing was available as Impulse-Responses.
Removal for “Use_Init_Output” to make Statistical-flow independent of 
Transient-flow,  is going to break the original intent where init and getwave 
were supposed to work in conjunction with each other handling linear and 
non-linear filtering portions respectively (as shown below)


I would go back to Arpad’s suggestion (year 2010) for having two 
Impulse-responses coming out of ami_init

-          One that goes to EDA tool for statistical flow

-          One that gets passed to getwave to allow splitting of 
modeling-effort across init and getwave and make things easy for linear filters.

BIRD120 was brought up that deprecates use of “use_init_output” with a view to 
keep statistical and time-domain simulations independent. But as I think more, 
we need to allow both capabilities. It absolutely does not make sense to 
implement simple linear filters within getwave when we can convolute the 
filter-IR with channel-IR. We should take all steps to make modeling easy and 
ensure enough flexibility.

This way, we cover both the scenarios – those who want to leverage init as 
complement to getwave and those who want to keep statistical-flow purely 
independent. Since this does not bring any disadvantage, I strongly feel that 
we all re-consider outputting two modified-IRs out of init function – one for 
statistical-flow and another one to complement getwave filtering.


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