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Rev F07 net length document

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xzsawq21
Junior(2)
Rev F07 net length document

Hello
I want to know about the Rev F07 net length.
I found and downloaded Rev B net length document. is there any differences between Rev B and Rev F net length?
I'm working with high Speed ADC and DAC (200MSPS) and I really need it.
 
Thanks

JFoster
Moderator(69)
Hello xsawq21,

Hello xsawq21,

We have the Rev F Net length report available for your download located here http://zedboard.org/support/documentation/4736

--Josh

xzsawq21
Junior(2)
my board is MicroZed ZYNQ

my board is MicroZed ZYNQ 7020.
even in the above link, I couldn't find anything about the Rev F07.
Thanks
 

JFoster
Moderator(69)
My apologies, for some reason

My apologies, for some reason I just assumed PicoZed. I have made a request for the Net Length Report.

--Josh

JFoster
Moderator(69)
Hi,

Hi,

I just posted the MicroZed RevF Net Length Report in the same location as the RevB Report.

Regards,

Josh

xzsawq21
Junior(2)
Dear

Dear
I want to rout  high speed LVDS pairs to MicroZed (200MHz)
I checked all the documents. the below pic is a part of the below document:
http://zedboard.org/sites/default/files/documentations/5274-MicroZed-Car...

as you see I have to tune the lengths within 10mils (no problem) but when I checked the Length Document that you have uploaded before I see 1 cm mismatch between the pairs on the MicroZed SOM!!!
even in the first blanket we have 16mm of mismatch between one pair (P to N)!!!
between the first and second pairs there is 24mm of mismatch!!!  it's disaster!
for JX1:

 
for JX2:

xzsawq21
Junior(2)
Dear

Dear
I want to rout  high speed LVDS pairs to MicroZed (200MHz)
I checked all the documents. the below pic is a part of the below document:
http://zedboard.org/sites/default/files/documentations/5274-MicroZed-Car...

as you see I have to tune the lengths within 10mils (no problem) but when I checked the Length Document that you have uploaded before I see 1 cm mismatch between the pairs on the MicroZed SOM!!!
even in the first blanket we have 16mm of mismatch between one pair (P to N)!!!
between the first and second pairs there is 24mm of mismatch!!!  it's disaster!
for JX1:
 
for JX2:

xzsawq21
Junior(2)
Dear

Dear
I want to rout  high speed LVDS pairs to MicroZed (200MHz)
I checked all the documents.
http://s9.picofile.com/file/8313829926/pairs.PNG
as you see I have to tune the lengths within 10mils (no problem) but when I checked the Length Document that you have uploaded before I see 1 cm mismatch between the pairs on the MicroZed SOM!!!
even in the first blanket we have 16mm of mismatch between one pair (P to N)!!!
between the first and second pairs there is 24mm of mismatch!!!  it's disaster!
for JX1:
 http://s8.picofile.com/file/8313829900/jx1.png

for JX2:
http://s8.picofile.com/file/8313829918/jx2.png

 

JFoster
Moderator(69)
Hello,

Hello,

Have you reviewed the MicroZed Carrier Design Guide?

http://zedboard.org/support/documentation/1519

--Josh

xzsawq21
Junior(2)
Yes, Actually I have sent you

Yes, Actually I have sent you a pic of this document above.
http://s9.picofile.com/file/8313829926/pairs.PNG
one of pins I have showed you is PUDC that I have marked it in the table with a red blanket. it's OK. I don't use it at all for the LVDS.
but my question is: I can tune all the lengths on my carrier board within 10 mils, but there is a mismatch in the lengths around 1cm on the MicroZed SOM!
what should I do?
 
Thanks

xzsawq21
Junior(2)
there is no answer?

there is no answer?
Actually this mismatch is negligible?
 
Thanks

JFoster
Moderator(69)
Hello xzsawq21,

Hello xzsawq21,

Please refer to the following information:

  • We made suggestions for pair matching and length tuning in the Carrier Card Design Guide , we did NOT say we routed our SOM to those numbers

 

  • We suggested those values as it provides reasonable effort to do, reasonable effort to manufacture without incurring HIGH costs (high performance routing = more $$), with good performance

 

  • You have chosen your pairs, so it will be your responsibility for matching your pairs.  For example, if those 4 pairs are used as a 4 lane BUS, then it is up to you to determine the tolerances and adjust the routing on the board accordiningly.

o   You will need to understand their worst case tolerances, which is typically driven by whatever you are hooking the circuit to

o   You will need to incorporate the differences we left on our SOM + package delay + your routing

  • You stated your worry in regards to 1cm of difference, this is very easy to account for on your custom carrier card, you just need to incorporate the OPPOSITE  - that is JX1-LVDS2_n will be LONGER on their board than _p by the exact distance that we have _p longer on the SOM.

o   Again, it all depends on WHAT you are hooking it to and what frequencies you are running at.

  • I hope that makes sense to you, for further support please contract a PCB house or contact your local Avnet FAE
  • We actually  are willing to provide you with our MicroZed Carrier Card files to make your adoption that much easier. For information on this please contact your local Avnet FAE.

Regards,

Joshua

fletch
Moderator(19)
@xzsawq21 -- did you include

@xzsawq21 -- did you include the internal Zynq package delays?

Bryan

xzsawq21
Junior(2)
No, you mean you have tuned

No, you mean you have tuned the length subject to the Zynq package delays? I think it's important for above 500MHz.
I have used your length document to tune the lengths in my carrier board.
I'd would be grateful if you had any idea. :)
Thanks

fletch
Moderator(19)
The MicroZed PCB routes were

The MicroZed PCB routes were originally tuned for the 7010 device in the CLG400 package. At the time of the MicroZed design, the specifications were very tight, especially in the case of the DDR3, which runs at 533 MHz. The specification was later extended to account for memory speed grade, which allowed us also to support the 7020 without changing the PCB. Several other interfaces were also tuned, all including the internal package delays.

 

Bryan