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LMH0387: Cable Line Driver vs. Cable Equalizer Power

Charles Harris
Prodigy 210 points
Part Number: LMH0387
Other Parts Discussed in Thread: LMH0397

Can I choose to make this IC operate solely as a Cable Line Driver by powering up VCCTX and leaving VCCRX disconnected or grounded?

Oppositely, can I make this IC operate solely as a Cable Equalizer by powering up VCCRX and leaving VCCTX disconnected or grounded?

Will both configurations still function as a proper Cable Line Driver or Cable Equalizer even with the disconnected or grounded pins? If so, am I supposed to leave them disconnected or ground them?

The data sheet talks about programming over SPI to distinguish the line driver as a cable equalizer or line driver, but I would like to hardwire the line driver and cable equalizer if possible. Please let me know. Thanks!

  • 0
    Prodigy 210 points

    Attached is the schematic that I would like to use where I have one LMH0387 "hard wired" to always be a Cable Line Driver and the other is "hard wired" to always be a Cable Equalizer. I would like to use as few connections as possible in this current design, so if this is this design would still function properly, please let me know.

    7080.LMH0387 Configurations.pdf

  • 0 in reply to Charles Harris
    TI__Guru* 93670 points

    Hi Charles,

    When using LMH0387 as a cable driver we need to provide power for the equalizer section even though it is not being used. By the same token, we need to do similar thing when using LMH0387 as equalizer. In this case, we need to provide power to the cable driver side as well. This is because un-used portion of the device provides AC ground for the section being used.

    Also, please note we have also introduced next generation LMH0387 device. This is LMH0397 and this part more functionality as well. Please take a look at this part as well.

    Regards,,,Nasser

  • 0 in reply to Nasser Mohammadi
    Prodigy 210 points
    Thanks for the quick response. Take care.