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  • TI Thinks Resolved

SN65MLVD200A: Is it allowed to short R-D and RE-DE?

Expert 3180 points

Replies: 7

Views: 45

Part Number: SN65MLVD200A

Hello E2E,

Is it allowed to short R-D and RE-DE?

what issue will occur?

Please help to double check the schematic as attachment.

Sincerely,

Jason

  • Hi Jason,

    You can short RE-DE but not R-D.

    Regards,

    I.K. 

  • In reply to I.K. Anyiam:

    I.K.,

    Thanks for your reply.

    My question is that what is the potential issue based on customer's schematic?

    Customer is suffering some of SN65MLVD200A no function.

    I am worried if the issue is related to their wrong connection.

    Sincerely,

    Jason

  • In reply to Jason Dai:

    Hi Jason,

    R and D should not be shorted together as the stub and additional loading from the driver/receiver can cause signal integrity issues.

    Regards,

    I.K. 

  • In reply to I.K. Anyiam:

    I.K.,

    Is it possible to damage IC when R and D short together?

    This product is in the stage of mass production.

    Customer did A-B-A swap and the issue followed IC.

    Please help to take a look their schematic again and give us the comment based on our question above.

    Sincerely,

    Jason

  • In reply to Jason Dai:

    Hi Jason,

    What exactly is the issue the customer is seeing? What's the difference in performance between the bad device and the good devices? Can you provide more details?  

    R and D should not be shorted together but I don't think it would damage the device.

    Regards,

    I.K. 

  • In reply to I.K. Anyiam:

    i.k.,

    Customer configure SN65MLVD200A to be the function of bidirectional buffer to transmit GPIO signal.

    That's a reason why customer short R-D and RE-DE. After we detail review and analysis the circuit again, we didn't see any potential issue to damage IC.

    How about your thought?

    The issue customer saw is no signal output at A/B as pin6/7 when they send Hi at D and DE.

    They do A-B-A swap, and the issue follow IC. after they replace a new IC, the issue could be fixed.

    we also want to know if their connection is not strong recommended and SN65MLVD200A is not suitable in this function. please help to advise.

    Sincerely,

    Jason

  • In reply to Jason Dai:

    Hi Jason,

    On the bad unit, what happens if they remove the short on R and D (desolder R1488 and R1485)? Is there still no output on A/B?

    Regards,

    I.K. 

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