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TMS570LC4357: DP83630 with TMS570LC43x – replacing RJ45 MagJack with AFBR-57E6APZ optical module

MOHAMED ASHEEQ
Prodigy 26 points

Part Number: TMS570LC4357
Other Parts Discussed in Thread: LAUNCHXL2-570LC43, DP83630

Hi TI Team,

I am using the LAUNCHXL2-570LC43 / TMS570LC43x board with the onboard DP83630 PHY.

I would like to replace the RJ45 MagJack (J11) interface with an Avago AFBR-57E6APZ fiber transceiver module for optical Ethernet communication.

For initial testing, I have taken the PHY-side signals TD+, TD−, RD+, RD− from J11 and connected them to the Avago module.

Could you please confirm:

- Is DP83630 compatible with this optical module?
- Can the RJ45 section be bypassed/replaced with this fiber interface?
- Is there any reference schematic / recommended coupling and termination network for this connection?

Please let me know if this approach is valid.

Thank you. 

  • 0
    TI__Guru* 76706 points

    Hi Asheeq,

    We never implemented this on practical from our end.

    However, the similar PHY seems to use for fiber optic and succeeded, please refer below thread to understand the same:

    (+) DP83640 - Interface forum - Interface - TI E2E support forums

    And also, we have internal AI and we get some good suggestions from it, you can refer them as well:

    Compatibility Assessment

    • Yes, the DP83630 PHY can work with the Avago fiber module with proper interfacing. The DP83630 has standard differential transmit/receive interfaces that can be adapted to work with the fiber transceiver.

    • The RJ45 section can be bypassed since you're directly connecting to the PHY-side differential signals (TD+/-, RD+/-).

    Important Implementation Considerations

    1. Signal Level Adaptation:

      • The DP83630 PHY uses voltage levels designed for twisted pair Ethernet
      • The Avago AFBR-57E6APZ expects specific signal levels for optical transmission
      • You'll need proper AC coupling and termination

    2. Coupling Network Requirements:

      • AC Coupling Capacitors: Use 100nF capacitors in series with each differential signal line
      • Termination Resistors: Add 100Ω resistors across each differential pair at the receiver side
      • Biasing Network: The Avago module may require biasing resistors to establish proper DC operating points

    3. PHY Configuration:

      • Configure the DP83630 for standard MII/RMII operation
      • Disable auto-negotiation features that depend on copper-specific signaling

    Recommended Connection Approach:

    DP83630 PHY               AFBR-57E6APZ
    ----------- ------------
    TD+ -----||------ 100nF -------→ TX+
    TD- -----||------ 100nF -------→ TX-
    (100Ω across TX+/TX-)
    RD+ ←-----||------ 100nF --------- RX+
    RD- ←-----||------ 100nF --------- RX-
    (100Ω across RX+/RX-)
    --
    Thanks & regards,
    Jagadish.