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TRF7970A: TRF7970A || RFID Aunthication Failure

Ankit Dubey
Prodigy 10 points
Part Number: TRF7970A


Tool/software:

We are currently using the TRF7970ARHB  IC in our communication boards, and we have encountered issues related to RFID authentication .
After conducting an analysis, we found that the TX and RX signals are not being generated in non-working boards following the NFC polling command, whereas all other parameters such as voltages, clock signal, and crystal waveform appear normal across both working and non-working boards.Please find this below report .

We interchanged the IC between the working and non-working boards. The IC from the working board functioned properly on the non-working board, but the IC from the non-working board did not work on the working board, indicating that the IC is faulty.

Till now we have assembled more then 1000 devices in production and we faces this issue in almost 50 devices , We have also prepared a report detailing the observed issues, including X-ray analysis and signal comparisons and X-ray are fine as compare to working board so  Please provide your recommendations for reducing failure rates during production , and effective methods for detecting these issues during board-level testing without connecting the antenna board.

Please provide your recommendetion for finding RCA for this issue .


  • 0
    TI__Guru**** 191906 points

    Hi,

      What are connected to TX and RX pins? They are open on your schematic. 

    The datasheet has an example impedance matching circuit for connecting to the antenna. This app note on best practice for antenna is also useful. Antenna Design Guide for the TRF79xxA (Rev. C)

  • 0 in reply to Charles Tsai
    Prodigy 10 points

    Hi Charles ,

    TX_OUT and RX_IN1 & RX_IN2 connected with the respective net in schematic please find this below image 

    Please find the attached rfid cirucuit diagram in pdf 

    RFID circuit Diagram

  • 0
    TI__Guru**** 191906 points
    Ankit Dubey said:
    Till now we have assembled more then 1000 devices in production and we faces this issue in almost 50 devices

    I really don't know the reason for these failures. Maybe we can start with a question as to where did you purchase the devices from? From TI directly?

  • 0 in reply to Charles Tsai
    Prodigy 10 points

    Hello Charles, 

    We have used this TRF7970ARHB IC from the Texas Instument in our design for RFID communication and currently we are running the  production line and we are facing that RFID aunthication is not working after the complete device assembly  and failure rate is almost 7% .

    we purchased this IC directly from the texas instument 

  • 0 in reply to Ankit Dubey
    Prodigy 10 points

    Hello Charles,

    We are waiting for your responce  

  • 0 in reply to Ankit Dubey
    TI__Guru**** 191906 points
    Ankit Dubey said:
    we are running the  production line and we are facing that RFID aunthication is not working

    Hi,

     Can you explain what are you trying to do with RFID authentication? Are you doing any testing between the reader/writer and the tags? Do you have the antenna present on your circuit? Or are you testing between the TRF7970A and the host MCU only? I must also say I'm not an expert in this device. 

  • 0 in reply to Charles Tsai
    Prodigy 10 points

    Hello Charles, 

    will it be any problem in RFID Ic if we will do validation without connecting RFID antenna? We are doing first PCB validation without connecting RFID antenna and and we are  after that complete assembly (having antenna assembly also) we are having validation with actual RFID tag and at this stage we are having failure of RFID.
  • 0 in reply to Ankit Dubey
    TI__Guru**** 191906 points

    Hi

    Ankit Dubey said:
    will it be any problem in RFID Ic if we will do validation without connecting RFID antenna?

    Ultimately you would need the antenna in a full systems to validate proper functioning between the reader and the tags.  On you schematic, I don't even see the host controller. This is why I asked if you are doing any testing (e.g. authentication) between TRF7970A and a host processor.  

    Why don't you run a test including the antenna to see if you can read/write to some tags and observe if the TX and RX are active? 7% failure rate is an extremely high rate and I suspect it is an IC problem at the moment. I have looked your schematic that you sent to the local FAE. I compare against the reference schematic on the datasheet and I don't really spot a major difference. 

    In the TRF7970A Chip Status Control Register, how and if you program the various control bits? 

    Can you even read and write to the various TRF7970A registers via the SPI interface? Can you show a scope cap of the SPI transactions between TRF7970A and the host controller?

    Did you initiate a transmit operation?

    What is your host controller?