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ISO3082: Looking for Isolated RS485 design Half duplex with Max node

surya
Expert 2395 points
Part Number: ISO3082
Other Parts Discussed in Thread: TIDA-00333, , ISO1412, SN6501, ISO1410

Tool/software:

Dear Experts,

We are currently in search of an RS-485 half-duplex isolated design with auto direction control. After some research, we found the following link to a TIDA-00333, which offers complete isolation with automatic direction control for the RS-485 repeater. We plan to adopt half of this design for our own system, but before proceeding, we would like to discuss it with experts to reach a final decision.

Our requirements are as follows:

  1. The input voltage (3.3V) needs to be isolated. We are looking for the best and most upgraded solution for this.
  2. Auto direction control using a Schmitt trigger, such as SN74LVC2G14DBV.
  3. An isolated RS-485 IC, such as ISO3082.
  4. Protection for the transmission lines to handle the maximum possible conditions.

We would appreciate your expert feedback to ensure we are heading in the right direction.

Thank you for your time and support.

Best regards

Surya

  • 0
    TI__Mastermind 30405 points

    Hello Surya, 

    Thank you for reaching out. ISO3082 will still work and provide the functionality desired. ISO1412 is part of the newest family of isolated transceivers and can provide additional Bus I/O protection (±30kV HBM; ±16kV IEC 61000-4-2 Contact discharge; ±4kV IEC 61000-4-4 Electrical fast transient). The family will also have higher speed options that may be helpful as well. 

    Best,
    Andrew

  • 0 in reply to Andrew J
    Expert 2395 points

    Hi Andrew J,

    Thank you for your prompt response. Could you please suggest the best power supply with isolation and a driver IC for this design? We need to finalize this design as soon as possible, so we are unable to conduct in-depth research ourselves. Therefore, we are looking for an evaluation board that includes a fully isolated power supply and transmission lines.

    Additionally, we require auto-direction control, and we were considering using a Dual Isolated Half-Duplex RS-485 Repeater that employs a Schmitt trigger for direction control. Could you please share your thoughts or suggestions on the direction control?

    We would appreciate your help in selecting the following components:

    1. Isolated power supply module and driver IC (if a power supply module is recommended).
    2. As per your suggestion, we will use ISO1412 for communication.
    3. Auto-direction control.

    Thank you in advance for your assistance.

    Best regards,
    Surya

  • 0 in reply to surya
    TI__Mastermind 18325 points

    Hi Surya,

    Please give us some additional time to look into your response. We will respond on Tuesday.

    Regards,

    Aaditya

  • 0 in reply to Aaditya V.
    TI__Mastermind 30405 points

    Hello Surya,

    We have individual EVMs for each orderable. You can order the SN6501 EVM and connect it to the ISO1412 for evaluation purposes. 

    1. SN6501 and a transformer is one of the simplest solutions for isolated power.  The ISOW14x2 Isolated RS-485/RS-422 Transceiver with Integrated Power would be another option that integrates the transceiver and power. 
    2. ISO1412 can be used in place of ISO3082 to achieve the auto-direction control scheme used in the TIDA-00333 reference design.

    Best,
    Andrew  

  • 0 in reply to Andrew J
    Expert 2395 points

    Hi Andrew,

    Thanks for the response. The ISO1412 is full duplex, but we are looking for half duplex so that we can loop A to Y and B to Z. Will that work?

    Regards,
    Surya

  • 0 in reply to surya
    TI__Mastermind 30405 points

    Hello Surya, 

    Sorry about the confusion. I see that you need a half-duplex controller. You are correct, ISO1410 would be the proper recommendation for a half-duplex transceiver. 

    Best,
    Andrew

  • 0 in reply to Andrew J
    Expert 2395 points

    Hi Andrew J,
    Thanks for the confirmation...

    Surya