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TMAG5273: Tamper detection

Shota Mago
Expert 8120 points
Part Number: TMAG5273

Hi team,

My customer considers to use TMAG5273 for tamper detection and they're asking some questions.

  1. While main power supply is off, the device will be operated from coin cell battery whose voltage range is 3V => 2V.
    Is there concern of accuracy degradation due to change of supply voltage?
  2. In page13, the datasheet states "Once the magnetic threshold cross is detected, the device asserts a fixed width interrupt signal through the INT pin, and goes back to stand-by mode. ".
    The customer needs automatically transition to Wake-up & Sleep mode without communication from MCU after assertion of /INT.
    Does TMAG5273 automatically transition to Wake-up & Sleep mode after tgo_sleep of SCL(20us)?
  3. Does placing permanent magnet affect something other ICs like DCDC, op-amps, CPU etc?
  4. Is special consideration needed for peripheral magnetic field the device?
    (e.g. At near Power Plant, the device might not work properly because of strong peripheral magnet field)

Best regards,

Shota Mago

  • +1
    TI__Mastermind 21120 points

    Shota-san,

    Thank you for reaching out with your questions.

    1. The operating range of the device was exercised when characterizing the sensing accuracy and linearity of the device.  While there may be some variation in performance due to changes in Voltage, the device should remain within the specifications shown in the electrical table.
    2. TMAG5273 will remain in standby mode after the interrupt.  In order to return to wake and sleep it requires the controller to set this mode again.
    3. Typically any impact from a permanent magnet would be very small if any unless there are nearby ferromagnetic objects.  A moving magnet can produce eddy currents in metals though, and if the changing field is oriented correctly, can generate current through a wire.
    4. When a strong external magnetic field is present it may interact with the field produced by the sensing magnet.  TMAG5273 will detect the field as present at the sensor location, so if the external field is strong enough to over-power the field from the magnet then this is what will be measured by the device.  Typically, however, this requires a very significant external magnetic field.

    Scott

  • 0 in reply to Scott Bryson
    TI__Expert 8120 points

    Hi Scott-san,

    Thank you so much for detailed answer!

    Best regards,

    Shota Mago