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DP83822I: DP83822 100M-FX packet loss

Part Number: DP83822I

     We are using DP83822 (single port 10/100 Mbps Ethernet PHY Transceiver) connected to SOC(zynq 7020) in one of our designs , The electrical interface (RJ-45) is tested and is working fine.We have made necessary Hardware modifications to connect to the Fiber Interface, But we are facing issues while configuring the Fiber interface.We use PC and optical modem connecting it through SFP, the ping is working but  have packet loss .

    we have check the important RMII signal (Clock and TX timing, setup and hold time, clock rise/fall time) between MAC and PHY, according to the datasheet, the signal is OK.

    So, maybe there is something wrong between the optical module and PHY, here is the schematic and optical module datasheet ,please help me check, thanks.AFBR-5803AQZ and AFBR-5803ATQZ.pdfPAGE06_DP83822.pdf

  • Hi,

    There are three things that stand out from the schematic capture:
    1. Are you using the DP83822IF? The DP83822I does not support fiber.
    2. You should use the SD pin (LED_1) and have it configured with the SD of the fiber transceiver you are connecting to. SD must be enabled through bootstrap along with FX to enable to feature.
    3. DP83822IF is a CML driver and not a LVPECL, which means you need the 0.1uF DC blocking caps. Please add 50 ohm pull-ups on the DP83822IF side and the LVPECL biasing on the fiber transceiver side.