Post Go back to editing

ADN4697E max length?

Hallo,

I have a question about ADN4697E (See attached Document).

We will use ADN for the Bus communication with servo drives with 100 MHz Clock frequency.

How many Nodes can i connect for this bus?

Can i use Cat5 cable and RJ45 Connector?

Have you any suggestion for PCB Design?

Thanks

Thanks

Best Regardsbest regards

adiScanM_LVDS.pdf
  • Hello,

    Up to 32 nodes can be connected to an M-LVDS bus. For your application, the number of nodes you can support depends on the bus length you choose, the cable and connector losses and then the acceptable jitter in your system.

    For Type 2 receivers such as the ADN4697E, 20 metres is a conservative guideline for total bus length at 100 Mbps. Generally the slave nodes should be spaced evenly along the bus and the master node should be at one end (next to the termination), as per your diagram, with extra spacing between the master and first slave node. Please refer to the ADN4697E datasheet for an application diagram - the one you attached in this discussion has master Y and Z connected to the wrong lines (master Y should connect to slaves A, master Z to slaves B).

    CAT5E cable (shielded cable would be preferred) and RJ45 connectors are commonly used with M-LVDS but you can check the manufacturer specifications to determine the losses from the cable and connectors. This will allow a more precise calculation of possible bus length. The TIA/EIA-899 standard specifies that the interconnect should result in maximum losses of 6 dB.

    The PCB trace length is also a factor in the transmission losses and reflections from stubs. The distance from the ADN4697E to the connectors should be minimised, the trace impedance should be controlled and the A and B trace lengths should be the same, as should Y and Z. Avoid routing single ended signals alongside or across the differential traces, route A and B together and Y and Z together (but avoid placing the two pairs directly beside each other).

    Best Regards,

    Conal

  • Thank you,

    Hallo,

    Is it possible ADN4697- application without common grounding system to both receiver and driver for dc -50(100) MHz switching rates?

    Can you give me  requirements for cabling shielding and grounding?

    best regards

    ADN4697.pdf
  • The ADN4697E has a common mode range of -1V to +3.4V. This should be adequate for your application not to require a common ground system.

    As regards the cable shield, it would be recommended to connect it to a chassis or earth connection at one point on the cable.

    Best regards,

    Conal