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Re: [BP] Interference tolerance test channels



Title: Message

Hi Joel,

All that’s OK as long as we don’t double count the EIT voltage for channel self interference. I suspect well have a good meeting today. J

… Rich

 


From: Joel Goergen [mailto:joel@FORCE10NETWORKS.COM]
Sent: Thursday, January 19, 2006 10:56 AM
To: STDS-802-3-BLADE@listserv.ieee.org
Subject: Re: [BP] Interference tolerance test channels

 

Rich,

Most of the materials cut out are the result of the high end changing, not the low end.  Your simulation assumes that Dk and Df are constant across freq, length, temp, and humidity.

If you lower the last 8Ghz of the model, you will gain back the ability to use fr-4 in some cases across production volumes.

My personal opinion is that we are making the EIT channel concept tougher then it needs to be.  It seems to me that us guys designing back plane channels could bear some of the burden rather then taking it out on the receiver and transmitter.

I would suggest going back to the old channel equation constants, raising 4 to 5Ghz by about 1.5dB, and then assign a small group to develop a real channel as the minimum floor in design practice, material construction, etc .... using this channel as the minimum test channel.  Sort of what we were about to do 2 years ago, but not quite that deep.  Then there are no arguments as to what the minimum EIT should be and how to get it there ... simply because it 'is' there.

-joel

Mellitz, Richard wrote:

Actually that’s backwards of what I did. I adjusted parameters to move the line up 3dB with out affecting the 1GHz characteristic very much. I though that’s what we were talking about at the dinner meeting. Then I created a channel to fit that line that had little return loss.

 

The intent was to create an EIT test channel where we could control interference and not a real 1 meter backplane channel.

The channel has no connectors (step dielectric launch) and has targets of:

Trace wide=3.6 mil spacing =6.5mil

Length 37.69 in

Plane space = 9 mil

Symmetric Stripline ~ ½ oz

Er 4.4 tand 0.0117

Surface roughness= 0.915 micron

17degree routing

Target mean that it wound need tuning but initial values would be close enough get you started.

 

Also If we pay $$$ for BERT why wouldn’t we expect to pay $$ for a test channel?


I’m also wrestling with the something else too. It seems that since we add interference to the EIT channel which effectively adds in return loss and crosstalk, why should AF max be the approximately the same since it does have return loss and via effects.  Maybe we need a different line for EIT channel and AF max.

… Rich

 

 


From: Joel Goergen [mailto:joel@force10networks.com]
Sent: Wednesday, January 18, 2006 9:01 PM
To: Mellitz, Richard
Cc: STDS-802-3-BLADE@listserv.ieee.org
Subject: Re: [BP] Interference tolerance test channels

 

Rich,
I looked at your data and it looks like you just changed the channel equation constants to fit the limit line to the data.

If we adopt this, in general, we eliminate the use of several glass constructions and pretty much any feature set less then 5mils.

Is this what you meant to do?
-joel

Mellitz, Richard wrote:


Oops… missed one.

Sorry,L

Rich

 


From: Healey, Adam B (Adam) [mailto:ahealey@AGERE.COM]
Sent: Wednesday, January 18, 2006 4:48 PM
To: STDS-802-3-BLADE@listserv.ieee.org
Subject: Re: [BP] Interference tolerance test channels

 

Rich,

 

Please be advised that your presentation title page contains a confidentiality disclaimer.  I will disable access to this file via the reflector archive.  I would recommend that you re-post an appropriately scrubbed version.

 

Thank you,

-Adam

 

-----Original Message-----
From: Mellitz, Richard [mailto:richard.mellitz@INTEL.COM]
Sent: Wednesday, January 18, 2006 4:09 PM
To: STDS-802-3-BLADE@listserv.ieee.org
Subject: Re: [BP] Interference tolerance test channels

Did it!  I built a channel that has 3db less loss at 5GHz with out impacting the loss at 1GHz. Also I created the AF coefficients to match this channel. See attached zip file.  I also checked the causality of the s4p as well. J

…Rich


From: DAmbrosia, John F [mailto:john.dambrosia@TYCOELECTRONICS.COM]
Sent: Monday, January 16, 2006 3:31 PM
To: STDS-802-3-BLADE@listserv.ieee.org
Subject: Re: [BP] Interference tolerance test channels

 

Steve,

But also realize that the general line also has built in margin for it to account for temperature, environmental, and  material variation as well.  The line as currently proposed has to be examined to look at from several aspects.  For example, the Molex channels are hugging the new proposed 23 dB line.  5” are on the daughtercard and 35” are on the backplane, which uses a typical 7 mil line.  So we are saying that to meet the skin effect at the lower frequencies we need a 7 mil wide line?  I think that is too far.  Look at the attached figure – 7 mil wide traces hug that line.  I think we have moved it too far upward.

 

I don’t see any efforts yet on reducing the problem via the crosstalk aspect of the problem.  Has that been abandoned?  I don’t think all of the burden at this time should be shifted to the channel, but should also be shared with the total allowable crosstalk.  Many of the channels did have margin.  We should look to striking a balance between the two.

 

John

 

-----Original Message-----
From: Steve Anderson [mailto:steve.anderson@xilinx.com]
Sent: Monday, January 16, 2006 2:52 PM
To: DAmbrosia, John F; STDS-802-3-BLADE@listserv.ieee.org
Subject: RE: [BP] Interference tolerance test channels

 

 

            John, all:

 

            But does a line made with the squared and cubed terms create a physically realizable channel?

 

            In the real channel I think there may be only two variables to play with:  skin effect and dielectric

absorption.  If we base simulations on something other than this, then I think bad things can happen like

non-causal effects.

 

            Steve A.

 

 


From: DAmbrosia, John F [mailto:john.dambrosia@tycoelectronics.com]
Sent: Monday, January 16, 2006 1:34 PM
To: STDS-802-3-BLADE@listserv.ieee.org
Subject: Re: [BP] Interference tolerance test channels

 

Guys,

Goergen asked the magic question.  Is it possible?  Yes it is.  We have a squared and cubed term to play with.  I am hoping Joel has some suggestions as well.  I just had a chance to do a quick scan and saw this.  I will be working on this stuff tonight

 

John

 

-----Original Message-----
From: Oganessyan, Gourgen [mailto:Gourgen.Oganessyan@MOLEX.COM]
Sent: Monday, January 16, 2006 2:24 PM
To: STDS-802-3-BLADE@listserv.ieee.org
Subject: Re: [BP] Interference tolerance test channels

 

Rich,

 

I see now what you refer too. I am not sure how you physically relaize a channel you are suggesting, keep low freq the same and come up at 5 GHz? Any physical channel should result in a tilted line?

 

Gourgen

 

-----Original Message-----
From: Mellitz, Richard [mailto:richard.mellitz@INTEL.COM]
Sent: Monday, January 16, 2006 1:05 PM
To: STDS-802-3-BLADE@listserv.ieee.org
Subject: Re: [BP] Interference tolerance test channels

 

 

The line didn’t only tilt. It also shifted. John D looked at a few channels as I attached. If we shift, it’s got an impact for KX and KX4.

…Rich

 

 

 


From: Joe M Abler [mailto:abler@US.IBM.COM]
Sent: Monday, January 16, 2006 1:15 PM
To: STDS-802-3-BLADE@listserv.ieee.org
Subject: Re: [BP] Interference tolerance test channels

 


The new channel appears to be inline with what we stated - a tilt of the line from DC to about a 3dB drop at 5GHz.  Why do you feel the lower frequencies need to stay fixed?


Thanks,        Joe


Joe Abler                                                             abler@us.ibm.com
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"Mellitz, Richard" <richard.mellitz@INTEL.COM>

01/16/2006 10:41 AM
Please respond to "Mellitz, Richard"

       
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        Subject:        Re: [BP] Interference tolerance test channels




Hi Charles,
DC and low freq's went down way to much! Can you create a model with the
same losses at say 1GHz or so and 2 dB less at 5GHz? I thought that's
what we agreed.
... Rich

-----Original Message-----
From: Charles Moore [mailto:charles.moore@avagotech.com]
Sent: Friday, January 13, 2006 8:42 PM
To: STDS-802-3-BLADE@listserv.ieee.org
Subject: [BP] Interference tolerance test channels

guys,

    I propose that we use the model ITTC_23.s4p for reduced attenuation
EIT modeling.  If it really will not work, ITTC_20.s4p is available as a
bail out channel.  If it looks too easy, let me know and i will step it
up just
a tad.

    The numbers refer to the fitted attenuation at 5.15...GHz.

                                 charles

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