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THVD1406: THVD1426DR

Basavaraj L
Prodigy 30 points
Part Number: THVD1406
Other Parts Discussed in Thread: THVD1400

Tool/software:

Please help us to design the circuit for RS-485 communication, I am facing the issue with TX data eco back along with my data reply. How can i avoid this eco data.

Also let me know how to control these RE & SHDN pins in hardware design. For making RE (High) and SHDN (low) i am facing this issue.

Thanks & Regards,

Basavaraj

  • 0
    Guru 316960 points

    Transmitted data is always echoed back (because a high input signal cannot be distinguished from an idle signal). If you want to avoid this, you have to control the driver and receiver separately with a transceiver that has DE/RE inputs.

  • +1
    TI__Guru 73201 points

    Clemens is correct.

    THVD1406 has a feature that echo's back the sent data on TX even when RE is disabled. 

    "When RE is logic high or left open and D input switches from logic low to logic high, the receiver output is high-impedance for the duration of tdevice-auto-dir. After the duration of tdevice-auto-dir, the receiver turns ON and outputs a logic high or low depending upon the differential bus input voltage."

    If you want to move away from this feature, you can look at THVD1400 as it is pin to pin with the THVD1406.

    -Bobby