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DS125RT410: Disable RX Gain

Mitchell
Expert 4915 points
Part Number: DS125RT410

Hi Team,

Is there any way the DS125's receiver gain can be turned off? Specifically, my customer would like to know if there is a bit in one of the registers that controls the gain such that when turned off, the eye diagram voltage reflects the actual voltage that appeared on the receiver pins.

Thanks,
Mitchell

  • 0
    TI__Mastermind 43795 points

    The receiver can be forced to minimum CTLE with registers.  Then the eye opening in the monitor will be as close as possible to the waveform at the device pins.

    Regards,

    Lee

  • 0 in reply to Lee Sledjeski
    TI__Expert 4915 points
    Hi Lee,

    Thanks for the quick reply.

    From the DS125 spec, it is described that even if we program our own CTLE boost values, the chip can override them in the event of a LOCK loss. But later it is explained that steps 1 to 5 (outlined in section 7.5.8) can be used to manually override CTLE boost under all* conditions. So, a couple questions based on this:

    1) Does this mean that in the event of a lost LOCK due to programmed CTLE values, the chip will not try to override these registers?

    2) Is loss of LOCK fatal in such a scenario?

    3) Can you please confirm that steps 1 to 5 (outlined in section 7.5.8) is the only thing needed for us to achieve this?

    Thanks,
    Mitchell
  • 0 in reply to Mitchell
    TI__Mastermind 43795 points

    From the DS125 spec, it is described that even if we program our own CTLE boost values, the chip can override them in the event of a LOCK loss. But later it is explained that steps 1 to 5 (outlined in section 7.5.8) can be used to manually override CTLE boost under all* conditions. So, a couple questions based on this:

    1) Does this mean that in the event of a lost LOCK due to programmed CTLE values, the chip will not try to override these registers?

    (Lee):  What values forced using steps 1-4 the chip cannot alter the CTLE values.

    2) Is loss of LOCK fatal in such a scenario?

    (Lee): If the chip loses LOCK there will be no output from the DS125RT410 and no eye monitor capability at the sampling point.  The chip will attempt to regain LOCK using the settings forced in steps 1-4 from section 7.5.8

    3) Can you please confirm that steps 1 to 5 (outlined in section 7.5.8) is the only thing needed for us to achieve this?

    (Lee): Yes it is confirmed.

    Regards,

    Lee