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Mobile Sensor using RF430FRL152 gets destroyed when passing strong fields

Thomas V
Prodigy 10 points
Other Parts Discussed in Thread: RF430FRL152H

A medical scientist informed me that a blood sugar measurement system (adhesive patch sensor) repeatedly gets destroyed when he passes admission controls for ski-lifts. He asked me for help on that problem.  I would like to ask if anyone knows about such issues associated with the RF430FRL152 chip.

The battery powered sensor uses the RF430RFL152 chip for wireless communication (printed antenna with approx. 25mm diameter). The skiing admission systems operate, such as the RF430, at 13.56MHz. They also use passive ISO 15693 cards. Obviously the RF430 is not tolerant against the magnetic field strengths of the lift system. In the chip datasheet there is no information about the protection of the antenna pins. Is there any kind of suppression element implemented? I assume that these lift systems use powers increased beyond ISO standard for higher people throughput.

Is it possible that high H-fields destroy the chip, or is there plenty of headroom? The manufactures of the blood sugar sensor know about this issue, but there were unable to do anything against it. So if the antenna pins were too sensitive, would it make sense to put a suppressor diode on the antenna, or to cover the sensor for skiing with aluminium foil of a few skin-depths (approx 0.1mm) for RF shielding?

Is there anyone  who also experienced damage due to other 13.56MHz RFID systems, or knows something about how to fix this problem.

Best regards

Thomas

  • 0
    TI__Guru* 90906 points

    Thomas - 

    this cannot be exactly correct, the lift systems interrogators still have to comply with EMC regulations and are well under the ISO15693-1 standard the cards and tags are supposed to withstand. The RF430FRL152H is made to be read by exactly these types of systems in the first place. Please provide more data here or contact me directly at josh.wyatt@ti.com to discuss.  

  • 0
    TI__Expert 7820 points

    It is unlikely that the RF430FRL152H is being damaged by the high RFID power field.  It is designed to withstand very high RF energy fields.  

    To determine if the RF430FRL152H is being damaged or not, there are a couple of things that may tried:

    1. When the RF430FRL152H is in the "destroyed" state, remove the battery to completely turn the chip off and then reapply power.  Test the ISO15693 commands like inventory. 

    2. If that does not reestablish communication, take the same chip and using JTAG verify that the RF ISR vector (0xFFF2) still has the correct value pointing to the RF interrupt service routine.

    Please let us know the result of these two tests and we can further help you with this issue.

  • 0
    Prodigy 10 points
    Hi Thomas,
    did you try what Alexander Kozitsky has suggested?

    I'm very interested in your problem as my product would also be used near skilifts gates.

    With regards,
    Olgierd
  • 0 in reply to Olgierd Szulc
    TI__Guru* 90906 points
    the original post is making reference to something we are aware of that occurred in one country on a related device and we determined root cause on that was that a sequence of commands that the library reader put out did not destroy the tag, but instead put it to sleep - because this is battery operated system (in this case), the stay quiet command worked a bit too well. - after a time, the timer inside the tag expired and the tag portion returned to normal state, ready for commands again. for that application, for the related device, this was resolved.

    i would recommend following Alex's suggestions and reporting back any actual issues you see, if any.