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RF37S114: DEMO of the NFC transponder with TRF7970A IC EVM

Bhargav_i
Prodigy 170 points
Part Number: RF37S114
Other Parts Discussed in Thread: TRF7970A, RF430CL330H, MSP430G2231, TRF7964A, TRF7960A

Hi,

I started a feasibility study for the NFC application.

I wanted to know the practical read range of "RF37S114" transponder to TRF7970A IC EVM Reader. Is it possible to have a DEMO for this scenario.

My application is - i want my reader to detect by passive transponder within 2cm.

I would like to know about "TRF7970A" NFC reader IC, how can i link this IC information to LIN interface, which micro controller would be better suit?

  • 0
    TI__Guru*** 128155 points

    Hello Bhargavi,

    We have done a study on the read range of the RF37S114 using a variety of antenna sizes which you can find here: http://www.ti.com/lit/an/scba035a/scba035a.pdf

    The TRF7970AEVM antenna is a good deal larger as even measuring from the center points of the coil it is 47mmx33mm which is much more than the app note. The RF37S114 can be read with it, but the range is extremely low when using the built in antenna, so you won't get a good demo from that as far as range goes unless you hook up an external antenna - which is exactly what is done in the above study.

    It should be noted the maximum range achieved as 1.65cm, so 2cm is beyond that already.

    I would recommend reading the study and then getting an antenna with the right size to meet your range specs to attach to the TRF7970A using an SMA connector.

    Regarding LIN, there are only a few TI MCU's which have LIN - I believe a subset of the C2000 family as well as some Hercules devices. We do not have example code on either of those platforms, but you could port one of our projects to either of those MCUs.

  • 0 in reply to Ralph Jacobi
    TI__Guru* 91086 points
    i could add here to look at a device like this: www.ti.com/.../sn65hvda100-q1.pdf
    which would be the LIN interface between the bus and any MCU (but probably with level shifters, too, depending on the MCU)
  • 0 in reply to Ralph Jacobi
    Prodigy 170 points

    Hi Ralph,

    Thanks for the Positive reply. 

    Could you please suggest me NFC Reader IC and TAG from auto grade part. As i mentioned this application is for automotive.

    Please let me know, if you need any other information.

    Thanks & Regards,

    Bhargavi U

  • 0 in reply to Josh Wyatt
    Prodigy 170 points
    Hi Josh,

    This part looks good.

    But i would be more happy if you can suggest me one MCU which consists of 8-bit MCU, LIN transceiver in one SOC.
    Application: Automotive, it would be good if that part is auto grade.

    Thanks & Regards,
    Bhargavi U
  • 0 in reply to Bhargav_i
    TI__Guru* 91086 points

    The RF430CL330H and -331H have been used inside the vehicle applications. (ISO14443B / NFC T4BT platform)

    The MSP430G2231 or -G2553 also have automotive variants. (16 bit MCUs...we don't make 8 bit MCUs here at TI, only 16 and 32 bit versions)

    could work for both the tag and the reader MCU. 

    The TRF7970A or TRF7964A would be suitable for the reader side, but to my knowledge it did not go through -Q1 testing yet - however, it does have high operating temp, which may be OK in your application, depending on the requirements and your testing.  

  • 0 in reply to Josh Wyatt
    TI__Guru*** 128155 points
    Hello Bhargavi,

    To confirm what Josh said, we do not have any NFC/HF RFID Reader ICs which are automotive qualified. If you need a guaranteed automotive qual'd reader IC to read the RF37S114, we do not have that.
  • 0 in reply to Josh Wyatt
    Prodigy 170 points

    Hi Josh,

    Could you please let me know, the dimensions of "RF430CL330HTB Board"

    Thanks & Regards,

    Bhargavi

  • 0 in reply to Bhargav_i
    TI__Guru* 91086 points
    that board measures 4.1cm x 3.6cm
  • 0 in reply to Ralph Jacobi
    Prodigy 170 points

    Hi Ralph,

    I have gone through the application report  which you have shared, its very good document for "Reader Antenna Optimization for Reading the RF37S114". As per the document the maximum range should be 1.65cm. and the chip supports ISO 15693 standard (Vicinity card - which have good enough range).

     I have two technical questions on this TAG usage:

    1) As per you above explanation, i didn't understood why the tag couldn't able to get read range with built in PCB antenna?? Always do we need to use external antenna? because final application will have internal antenna with reader right?? how can we use the tag for better read range??


    2) Is there would be any commands to operate this TAG transponder at 15693 standard??

    Because i tried testing the range of the TAG Transponder "RF37S114" with  Reader IC having "105 mm x 52 mm, two turns antenna" but when i touch the tag to the reader antenna then only its getting detected (1mm), even i checked the same TAG with Mobile also, but its also same case if i tap the mobile on TAG then only its getting detected, its not the case with other 14443 tags, am getting 5cm range for them.

    But as per the above explanation the maximum range is 1.65cm, which am not able to achieve it? so is there any thing which am missing? or how to check the read range using 15693 standard, is there any commands which i need to send from reader IC??

    Could you please help me??

    Thanks & Regards,

    Bhargavi

  • 0 in reply to Josh Wyatt
    Prodigy 170 points
    Hi Josh,

    Could you please help me on the below technical question:

    As i explained my application for automotive i need the reader IC.

    I have selected latest TI part , which is "TRF7970A" but as per its datasheet it supports only "NFCIP-1 & NFCIP-2" standards. So for my application this wont be the right part?? It wont support "ISO 14443 & ISO 15693" standards like "TRF7960A" ??

    DO i need to change my selection to TRF7960A??

    Thanks & Regards,
    Bhargavi
  • 0 in reply to Bhargav_i
    TI__Guru*** 128155 points
    Hello Bhargavi,

    HF RFID is based on magnetic fields, and the read range for tags are determined by the amount of coupling you can get between the reader and the tag's magnetic field.

    The RF37S114 has a very small antenna, meaning in general you will not get good coupling for it.

    This is by design, as it is not meant to be used at long range.

    The purposes of this tag is be an extremely small form factor tag which has limited range and takes up littler space in a system.

    The range we achieved was done by using the TRF7970A operating at 5V with the ideal antenna size to maximize the coupling ratio. It may be possible to get more using a more powerful reader but TI does not sell anything more powerful.

    Also Smartphones are terrible for this because of large antennas and comparatively less output power for shorter periods of time.

    If you want more range from ISO15693, you can get much larger tags. SAG and Smartrac both make many tags using TI Tag-It die in many forms.

    As for the IC Selection: TRF7970A supports all the modes TRF7960A supports plus Peer to Peer and Card EMulation

    I am not sure which datasheet you looked at but it's very clearly stated at the top:
    • Completely Integrated Protocol Handling for ISO/IEC 15693, ISO/IEC 18000-3, ISO/IEC 14443 A and B, and FeliCa™