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DS125MB203 design support

syed hamad
Expert 1120 points
Other Parts Discussed in Thread: DS125MB203

Dear Tier,

Please help us to get the Design detail documents on DS125MB203.requirement of 2:1 MUX with 10G SERDES lines

regards,m

syed

  • 0
    TI__Mastermind 43795 points

    Hi Syed,

    I can help you configure the DS125MB203.  Can you tell me a little more about the application and the components around the MB203?

    What are the input and output channel characteristics?

    Ser ->  ? dB loss @ 5Ghz -> MB203 ->  ? dB loss @ 5Ghz -> Des

    Also, will the Serializer be using any Transmit Equalization?

    Regards,

    Lee

  • 0 in reply to Lee Sledjeski
    Prodigy 40 points
    Hi Lee
    In our Application, we would like to provide a SW configurable solution to support either 12.5Gbps using XFP or 2.5Gbps using SFP, using a single SERDES interface from MAC device, which can configure the SERDES based on the application requirement. We have to support 4 such interfaces in our system. Based on this I was looking at using DS125MB203 (2 nos) to support our requirement.
    Our design stage is at Preliminary and we are drawing the Schematics with this device. As of now I can only guess the SERDES lengths, which could be (approximate estimation) as given below. I would like to understand do we need to provide option for "Pin configuration" using ENSMB or we can use the EEPROM itself for all the possible configurations. Do we have any reference designs to look at how are the pin configurations provided?

    TX:
    From the MAC to DS125MB203 D_IN <5inches
    From the DS125MB203_SOUT_A to SFP (2.5G) <5inches
    From the DS125MB203_SOUT_B to XFP (12.5G) <10inches

    RX:
    From the SFP to DS125MB203_SIN_A <5inches
    From the XFP to DS125MB203_SIN_B <10inches
    From the DS125MB203 D_OUT to MAC <5inches

    Thanks and Regards
    Karthikeyan
  • 0 in reply to Karthikeyan Subramanian
    TI__Mastermind 43795 points

    Hi Karthikeyan,

    You do not need to provide for pin control as well.  I would allow for SMBus slave and SMBus master mode in the schematic.  Having easy access to the registers is the quickest way to work through any debug or questions that come up.

    The only length which looks marginal is the 12.5G link between the MB203 and the XFP module.  I would work to place the MB203 closer to the XFP module to help keep the eye opening at the module wide open.  The XFP specification limits the loss to ~ 6 dB including the connector.

    The settings below are a good place to start

    EQ = 00'h (minimum)  //* I always recommend to start low and work up until optimal eye opening is seen.

    VOD = 010'b (800mV)  //* XFI eye mask ~ 820mV

    DEM = 000'b (minimum)  //* Assuming MAC has some receive equalization

    Regards,

    Lee

    Regards,

    Lee