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ISO1412: Termination resistor for both side at Full-Duplex

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Part Number: ISO1412

Hi Expert,

We are recommending the Both side(Receiver and Transmitter side) termination in the ISO1412 datasheet (P25, 10.1 Application Information, Figure34)

Also I found the following E2E session.

However, customer think, the termination is needed only Receiver side in case of Full-Duplex. Because the Full-Duplex is not bidirectional.

If customer use only receiver side termination, do you have any concern?

Could you please give me your advice?

Thanks

Muk

  • Hi Muk,

    Your understanding is partially correct that a termination is needed only at the receiver node to avoid any reflections and is not needed at the driver end. This applies only to the system where there are only two nodes. For a multi-node or multi-point system, this is not true as multiple slave receivers will be connected to a single master driver. Hence, termination on two far ends of a communication cable are required to keep the reflections minimal.

    Please refer to the single-master, multi-slave full-duplex configuration below. Here you will see that there are termination resistors on both the lines at the opposite ends of communication cable. Please do keep in mind that the termination resistors are to be connected to the two opposite ends of the cable and not to intermediate node, as also shown in the diagram below. If I have any further inputs, I will come back and post it here.

    Let me know if you have any questions, thanks.

    Regards,
    Koteshwar Rao