This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

DS125BR820: Recommend the Configuration for using JESD204B Repeater.

Part Number: DS125BR820

Hello

My Customer wants to use the DS125BR820 for the JESD204B Repeater

Recommend the Configuration if Set PIN MODE for the JESD204B Repeater.

Please Can you Recommend the Parameter?

JESD204B 9.8Gbps

  1. Rx Detect Settings
  2. Signal Detect Status Threshold Level
  3. Equalizer Settings
  4. Output Voltage Settings

Thank you

Regards.

  • Hi Louis,

    The optimal settings will depend on DS125BR820 placement within the JESD204B channel running at 9.8 Gbps.

    Here is an expample.

    ADC (JESD204B) Tx ->  PCB Trace (-8 dB @ 4.9 GHz)  ->  DS125BR820  ->  PCB Trace (-2 dB @ 4.9 GHz) -> FPGA Rx

    1. RX Detect - Pull to 1 (VIN in 3.3V mode, or VDD in 2.5V mode)

    2. Signal Detect - Default

    3. Equalizer setting - Level 3 of 4 (+ 8.6 dB)

    4. Output voltage setting - Level 3 of 6

    Regards,

    Lee

  • Hi Lee

    Thank you for your support.

    Please Can you Recommend the Parameter for this condition?

    FPGA (JESD204B) Tx ->  PCB Trace (-4.3 dB @ 4.9 GHz)  ->  DS125BR820  ->  PCB Trace (-4.3 dB @ 4.9 GHz) -> RFIC Rx
    RFIC (JESD204B) Tx ->  PCB Trace (-4.3 dB @ 4.9 GHz)  ->  DS125BR820  ->  PCB Trace (-4.3 dB @ 4.9 GHz) -> FPGA Rx

    Regards

  • Hi Louis,

    That seems like low loss for 30cm.  With the indicated loss I would use my previous recommendations.

    Regards,

    Lee

  • Hi Lee

    Thansks.

    Why Select the Output voltage setting Level 3?

    Is there a formula to Calculate the Output voltage Ratio?

    Regards.
  • Hi Louis,

    The datasheet does have some input to output voltage ratios in a table.  These are measured at ~DC with the ATE so the ratio is over reported.  Based on experience with SAS-3, 10G-KR, and PCIe I use the Level 3 setting to maintain the lower frequency waveform amplitude.  This technique allows for the best equalizer linearity and allows any adaption by the system Rx work optimally.

    Regards,

    Lee