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DS125BR111: Pin Mode, OUTA/B Output Amplitude Setting

Kenichiro
Mastermind 9165 points
Part Number: DS125BR111

[ DS125BR111 ] Pin Mode, OUTA/B Output Amplitude Setting

Hi,

Can you help me to understand the setting of the output amplitude of OUTA and OUTB?




According to the table5 footnote, the VOD output amplitude is set with the VOD_SEL pin.
Does this mean that any settings on VODA_DB and VODB_DB pins do NOT affect?

Or can you elaborate how VODA_DB and VODB_DB pins work to decrease the amplitude?

If the assumption above is correct, we cannot apply the different amplitude setting to OUTA and OUTB, correct?


Thank you for your support in advance.
Regards,
Ken

  • 0
    TI__Mastermind 43795 points

    Hi Ken,

    The amplitude is set with the VOD_SEL pin.  The VOD_DB pin function should always be tied to GND for normal operation.

    If there is an application which prefers to have an output voltage attenuated by more than the lowest VOD_SEL setting, then floating the VOD_DB pin would extend the possible range of signal amplitude attenuation through the DS125BR111.  In all known cases for PCIe and SAS/SATA we have not needed to adjust the VOD_DB pin to achieve compliant operation.

    In order to achieve independent and differemt channel output amplitudes, it is necessary to use SMBus register settings. 

    Regards,

    Lee