Re: [802.3_50G] Back Plane Loss Discussion

["Mellitz, Richard" <richard.mellitz@xxxxxxxxx>]

More powerful Si is more power too.

…Rich

 

From: Joel Goergen (jgoergen) [mailto:jgoergen@xxxxxxxxx]
Sent: Friday, January 15, 2016 11:49 AM
To: Mellitz, Richard; STDS-802-3-50G@xxxxxxxxxxxxxxxxx
Subject: Re: Back Plane Loss Discussion

 

I agree with you … but what margin are you looking for?

 

In the designs I target, 25dB has no value.  I would need retimers.  Retimers add space and power.  So if I add them on more then 50% of the links, then I should just as well set the power level to what I need it for to set the retimer number back into the 20ish% links requiring retimers.

 

Take care

Joel

 

From: <Mellitz>, Richard <richard.mellitz@xxxxxxxxx>
Date: Friday, January 15, 2016 at 8:17 AM
To: Joel Goergen <jgoergen@xxxxxxxxx>, "STDS-802-3-50G@xxxxxxxxxxxxxxxxx" <STDS-802-3-50G@xxxxxxxxxxxxxxxxx>
Subject: RE: Back Plane Loss Discussion

 

For this market, it is not only power but lower cost volume manufacturability.

 

I really need 60dB if I use the “fit in the shoe box” argument. J

 

… Rich

 

From: Joel Goergen (jgoergen) [mailto:jgoergen@xxxxxxxxx]
Sent: Friday, January 15, 2016 11:10 AM
To: STDS-802-3-50G@xxxxxxxxxxxxxxxxx
Subject: [802.3_50G] Back Plane Loss Discussion

 

All

 

My apologies for not starting this discussion sooner.

 

I understand the there is a lot of push-back for a 50G interface 32dB@14Ghz.

I would guess the reason is power related.

 

My argument is that if the limit is 25dB or 28dB, a significant amount of retimers will be required. And therefore the power per link will be almost double anyway.  So power isn’t an argument.

 

However, I would conceded to a lower loss level if we all agreed to completely define the retimer block and recognize it as a valid block function.

 

Take care

Joel