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AD9680 minimum JESD204B lane line rate

Category: Hardware
Product Number: AD9680

Hi,

I am evaluating an AD9680 and have an inquiry regarding the minimum lane line rate.
I had setup the device with 2 lanes, single converter and sample size (N') of 16. I then operate the sample clock at 300MSPS. The calculated sample rate is therefore 3Gbps
L = 2
N' = 16
M = 1
F_ADC_CLOCK = 300MSPS

I did not notice that the datasheet specify that the minimum line lane rate is 3.125Gbps, however, my receiver (based on a Xilinx Ultrascale FPGA) seems to work perfectly fine and does not detect and bit errors.

Where does the 3.125Gbps limitation come from?

It seems to imply that running at 300MSPS with a single converter at N' = 8 is impossible no matter how many lanes are used for the link.



Edited to add a comment about running at 300MSPS with N' = 8
[edited by: eniv at 9:29 PM (GMT -5) on 28 Nov 2022]

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    •  Analog Employees 
    •  Super User 
    in reply to eniv +1 verified

    Hi eniv,


    Actually based on figure 3 in the survival guide, the line lane rate can be anywhere between 312.5Mbps to 12.5Gbps.


    Yes that is correct.

    I checked other resources which explains the limit…

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  • Hi eniv,

    Thank you for your interest in AD9680.

    I did not notice that the datasheet specify that the minimum line lane rate is 3.125Gbps, however, my receiver (based on a Xilinx Ultrascale FPGA) seems to work perfectly fine and does not detect and bit errors.

    Where does the 3.125Gbps limitation come from?

    The 3.125 Gbps to 12.5 Gbps is in compliance with the JESD204B Standard. You may refer to this article for some details: JESD204B Survival Guide (analog.com)

    From the AD9680 Datasheet, on pages 73 to 74. Table 26 and Table 27 shows the output configurations supported for both N΄ = 16 and N΄ = 8 for a given number of virtual converters.



    It should work as expected as long as these supported JESD204B configurations are followed.

    Thank you.

    Best regards,
    Peevee

  • Actually based on figure 3 in the survival guide, the line lane rate can be anywhere between 312.5Mbps to 12.5Gbps.

    I'm well aware of the configuration tables and my settings appear valid based on them. The text you highlighted yellow is what I'm asking about.

    Until this morning I didn't realize that this limitation exist. I've been running the configuration that appears on line 2 on table 26 at 300MSPS (corresponds to a lane line rate of 3Gbps which is below the supported minimum) and everything is working just fine.

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  • Actually based on figure 3 in the survival guide, the line lane rate can be anywhere between 312.5Mbps to 12.5Gbps.

    I'm well aware of the configuration tables and my settings appear valid based on them. The text you highlighted yellow is what I'm asking about.

    Until this morning I didn't realize that this limitation exist. I've been running the configuration that appears on line 2 on table 26 at 300MSPS (corresponds to a lane line rate of 3Gbps which is below the supported minimum) and everything is working just fine.

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