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THVD8000: Polarity Free Operation

Nam, Dino
Expert 6235 points
Part Number: THVD8000

Dear team, 

The customer is considering design THVD8000 at their application. 

Currently, the customer are testing Polarity Free Operation using 2 x THVD8000EVM. but under second set up(A to B, B to A), communication is failed. 

As datasheet mentioned, I think reversing the polarity doesn't result in communication fail. please let me know your opinion regarding reason of communication fail. Is there any option of EVM setting to reverse the polarity?

 

Thank you. 

  • 0
    TI__Mastermind 25705 points

    Dino,

    The feature has been verified in the testing. What's the data rate, carrier frequency and distance? Can you capture the waveforms of both cases to see the difference? The possible explanation is that the application is close to the limit of the device's operation. For example, the clocks in each OOK bit is less than 5, or the attenuation of the cable is severe.

    Regards,

    Hao 

  • 0 in reply to Hao L
    TI__Expert 6235 points

    Hello Hao, 

    Please refer to the below

    Distance : 20cm , Cable : AWG24

    - Carrier frequency : 125 KHz , Data rate : over 38400 => communication fail , below 38400 => communication success   

    - Upper carrier frequency => no issue under any data rate. 

    Their target distance : 300m , carrier frequency, data rate and cable type is not fixed yet. 

    Could you recommend carrier frequency, data rate and cable type to success communication to 300 meter distance under polarity free operation.

    Thank you.    

  • 0 in reply to Nam, Dino
    TI__Mastermind 25705 points

    Dino,

    If the target data rate is 38400bps (~20kHz clock), I suggest you choose the carrier frequency 200kHz or higher. From our lab data, the carrier frequency up to 500kHz can work with 300m AWG24 cable. BTW, the cable selection is mainly governed by the power delivery functionality.

    Regards,

    Hao

  • 0 in reply to Hao L
    TI__Expert 6235 points

    Hello Hao, 

    Thank you for your kind comments. 

    We will test up to 300m distance soon with your recommendation, I will contact you again with test result. 

    Thank you.