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DS125MB203: about DS125MB203 MIN EQ

Vera Mao
Expert 5065 points
Part Number: DS125MB203

Hi dear supporting team,

in MB203 d/s, it seems even with EQ=0 setting, there is still around 3dB gain at 10Gsps, is there any special setting to make it smaller or bypass the EQ? and what's the difference btw 10GKR and 10GE mode? (any difference in EQ?) , And the gain of receiver channel will also be kept till TX channel, right?   TKS A LOT!

  • 0
    TI__Expert 7935 points

    Hello--

    For the DS125MB203, there is no setting that allow you to bypass the EQ.  There is some EQ gain even with the EQ=0 setting.

    The 10GE Mode provides limiting output driver while the 10GKR provides non-limiting output driver.  These modes don't affect the EQ.

    Regards,

    Davor

  • 0 in reply to Davor Glisic
    TI__Expert 5065 points

    hi Davor,

    thank you very much!  when will need limiting mode? is there any setting that could help set lower bias of the EQ to make the gain smaller at 0 setting? and also will the receiver gain be passed to the output? my customer has very low insertion loss over the SoutB to the other chip(<5dB), they sometimes find there will be BER here. we are doubting whether there is over compensate here, the reg setting of the chip is as below: do you think they need revise some of them?    tks!

    0x00,0x01

    0x06,0x18

    0x08,0x04

    0x16,0x00

    0x17,0xe8

    0x18,0x00

    0x24,0x00

    0x25,0xe8

    0x26,0x00

    0x34,0xe8

    0x35,0x00

    0x41,0x00

    0x42,0xe8

    0x43,0x00

  • 0 in reply to Vera Mao
    TI__Mastermind 43795 points

    Hi,

    We recommend using the 10G-KR mode for applications which have link training.  Alternately if link training is disabled, then using 10GbE mode with a limiting output drive can produce lower jitter numbers - especially with short channels and low loss.

    I do not see any issues with the register values. 

    The EQ cannot be lowered to less than the minimum value on this design.

    Regards,

    Lee

  • 0 in reply to Lee Sledjeski
    TI__Expert 5065 points

    Hi Lee,

    thank you very much!

    double check with you, customer is using Din--Sout direction,  when they choose OUTB, and let DIN--SOUTA unconfigured,(and no signal pass through it), they find OUTB link will have BER.  after setting DIN-SOUTA  channel EQ to minimum, then there is no BER show up at SOUTB link.  (they have run for more than 12h and no BER).

    So will DIN-SOUTA setting affect DIN-SOUTB even when there is no signal at SOUTA?  There finnal register setting is as below, anything else need be set? (bold font is the ones added from last one:

    Address    Reg
    0x00    0x01
    0x06    0x18
    0x08    0x04
    0x0f    0x00
    0x16    0x00
    0x17    0xe8
    0x18    0x00
    0x1d    0x00
    0x24    0x00
    0x25    0xe8
    0x26    0x00
    0x2c    0x00
    0x2d    0xe8
    0x2e    0x00
    0x34    0xe8
    0x35    0x00
    0x3a    0x00
    0x3b    0xe8
    0x3c    0x00
    0x41    0x00
    0x42    0xe8
    0x43    0x00

  • 0 in reply to Vera Mao
    TI__Expert 7935 points

    There is nothing else that needs to be set.

    Regards,

    Davor