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DP83867IR: Question about termination resistor setup

Part Number: DP83867IR
Other Parts Discussed in Thread: TIDA-010010, , AM5728

Hi all, my customer has some confusion about termination resistors in the RGMII interface between the MAC and this PHY.

 Most PHYs suggest adding termination resistors in series with all 12 of the interface lines.

The datasheet doesn't clarify, but this ref design app note does (https://www.ti.com/tool/TIDA-010010), but here is the conflict:

 

RGMII MAC Receive Signals/ PHY Transmit Signals

    • ENET1_RGMII_RXD[0..3]
    • ENET1_RGMII_RX_CTL
    • ENET1_RGMII_RX_CLK (RXC in SOM pinout)
  1. From the DP83867 related ref design: TI Designs: TIDA-010010, page 7, “The DP83867IR has integrated termination resistors in the RXD data lines, which are RX_D0, RX_D1, RX_D2, RX_D3, RX_CLK and RX_CTRL. Therefore there are no external line driver resistors needed to be added on the PCB between the DP83867IR and the [reference board processor]”
  2. Good. This seems clear.

RGMII MAC Transmit Signals/ PHY Receive Signals

    • ENET1_RGMII_TXD[0..3]
    • ENET1_RGMII_TX_CTL
    • ENET1_RGMII_TX_CLK (TXC in SOM pinout)

 

  1. From the DP83867 related ref design: TI Designs: TIDA-010010, page 8, “The TXD data lines, which are TX_D0, TX_D1, TX_D2, TX_D3, TX_CLK and TX_CTRL have line driver” resistors of 22 Ω added between the DP83867IR and the AM5728. Okay, this seems to indicate that they must place them on their design external to the PHY.
  2. But Table 2, page 9 of the DP83867 related ref design: TI Designs: TIDA-010010 States “RGMII TX termination resistors; DP83867 integrated” Is this a typo? Is the table meant to say RGMII RX termination resistors?

 Thanks!