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THVD8000: multiple slave and maximum number of slave?

AnBer
Mastermind 30150 points
Part Number: THVD8000

Team,

The blog show a point to point interfacing:
https://e2e.ti.com/blogs_/b/industrial_strength/archive/2020/06/12/how-rs485-transceivers-with-ook-modulation-simplify-bus-designs-and-lower-costs

-Can the THVD8000 support a std half duplex bus topology like the below?
Typically 1 MASTER (power src) and 100 SLAVE (power sink)


    
-Compare to a std RS-485 implementation what would be the additional factors that would potentially limit the number of slave?

Thanks in advance,

A.

  • 0
    TI__Guru 62920 points

    Hello,

    The same limiting factors that would restrict maximum node counts in an RS-485 network should be considered here as well.  The primary limitations with respect to data communication would come from:

    1. The leakage current from each additional receiver increasing the output current sourced from the driver, resulting in some loss of differential voltage amplitude due to the driver output impedance.

    2. The signal integrity degradations that could result from non-ideal wiring of each non-terminated node (i.e., if they connect to the main bus via some "stub" connection).

    In addition, there would be some limitations to consider with respect to power delivery - namely, that the master node must be able to source the required current for all slaves connected in parallel and that the resulting voltage drops (due to DCR of the coupling inductors and cabling) remain within the allowed range for the slave power supplies.

    If you haven't seen it, I'd recommend referencing this app note:

    https://www.ti.com/lit/an/slla496/slla496.pdf

    It describes some the implementation concerns with the THVD8000 device in more detail.

    Regards,
    Max