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RI-SMD-MRD2: Detect absence of antenna

Nick Gilling1
Prodigy 60 points
Part Number: RI-SMD-MRD2
Other Parts Discussed in Thread: MRD2EVM

Hi There,

We are wondering if it is possible for the RI-SMD-MRD2 to detect the absence of an antenna by monitoring output power or voltage levels? We are trying to figure out a way to detect whether our coil antenna is not connected or if a wire has become broken.

Thank you!

Nick

  • 0
    Prodigy 60 points

    Hi,

    We are also wondering the input logic levels for SIG_IN_0

    1. Absolute input range

    2. Vin_High_Min

    3. Vin_Low_Max

    Thank you!

  • 0 in reply to Nick Gilling1
    TI__Mastermind 18265 points

    Hello Nick,

    there is nothing implemented in the MRD2 that gives you the possibility to check the absence of the antenna. If you can implement a measurement of the supply current, you could switch on the 134.2kHz carrier frequency (Reference Guide page 91) and check if the current increases. Beside a direct measurement of the transmitted carrier signal, this is the only way that comes into my mind.

    For the SIG_IN_0/1 pins the Vin_High_Min = 2V and for Vin_Low_Max = 0.8V. It is a direct input to a 3.3V supplied 74LVC244 Buffer.

    Best regards,

    Helfried

  • 0 in reply to Helfried Vollbrecht
    Prodigy 60 points

    Hi Helfried,

    Thank you for the response!

    Is there any other way to indirectly detect absence of antenna? Or a suggested method for absence of antenna detection using external circuit? Just trying to turn over all possible stones.

    Thanks!

    Nick

  • 0 in reply to Nick Gilling1
    TI__Mastermind 18265 points

    Hello Nick,

    I took my board and tried out an idea that I had but it did not work.

    Beside the measurement of the current also the high output voltage at the antenna can be used as an indicator. I measured ~40Vpp at the MRD2EVM ANT1 pin which is only possible with the L existing in the resonance circuit.

    Then I am running out of ideas.

    Best regards,

    Helfried