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Max speed of GTH lines on TE0841 for JESD204B interface

Started by spr, May 19, 2017, 12:14:18 PM

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spr

Hello,

I have the following questions :

1) We see that the Samtec Razor beam connectors used in the TE0841 result in a stacking size of 8 mm. On the Samtec website (also on Trenz wiki) it is mentioned that the maximum serial line rate achievable for differential pairs is at max 14 Gbps for 5 mm stacking height and 13 Gbps for 12 mm. For single ended lines, the rating is much higher 23 Gbps for 5 mm and 15 Gbps for 12 mm. So, by simple extrapolation/line fitting, I would guess for 8 mm stacking height the maximum would be ca. 13.5 Gbps (for differential) and ca. 18 Gbps (for single ended). Could someone confirm this ?

2) Now, we intend to use the GTH lines of the TE0841 module for JESD204B interface at nearly 15 Gbps. Now given that JESD204B serial lines are differential lines, I have a feeling that our requirement is out of specification of the Razor beam connectors (which is 14 Gbps for differential pair) ? So, please let me know the maximum differential serial line rates that can be safely supported by TE0841 ?? Also, has Trenz performed any measurements w.r.t. GTH lines/JESD204B serial line rates ?

Regards,
Raju


spr

Thanks for the heads up ! So, I can assume that the TE0841 module/connector can support 12.5 Gb/s without any issues ?

JH

Hi,

what do you mean with "without any issues"?
We have done Ibert test TE0841 MGTs with 12.5Gbs on TE0841 with loopback over connectors without problems.
But there are more factors which can influence the quality of interface, you carrier and the trace routing and length, the interaction between the used JESD204B IP on the FPGA and on the opposite part...

br
John

spr

Hello John,

"We have done Ibert test TE0841 MGTs with 12.5Gbs on TE0841 with loopback over connectors without problems"  : This is exactly what I wanted to know if the connectors were actually tested for this speed or not !! thanks for the confirmation, it really helps...

Sure, we will take care of the board layout w.r.t routing and other interconnects. But, it would also be very helpful if you could suggest any document/material that could give us a good idea about board layout techniques, routing dos/donts etc which we should take care for the GTH lines in our custom carrier board to achieve such high speed of 12.5 Gbps ??

Thanks once again !