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TMS3705: Is TMS3705DR a valid device?

Part Number: TMS3705

Hi,

In this crazy world our product manufacture is halted by nil stocks of RFID chip TMS3705DRQ1. A well known U.S. component source offers TMS3705DR without the Q1 postfix. The devices are offered with date codes 0049 or0401.

ie TMS3705DR Date Code 0049

    TMS3705DR Date Code 0401

What is the significance of the Q1 postfix and the date codes.  Can I use these devices to replace the TMS3705DRQ1 ?   or should I try a small number before ordering in quantity.

Any advice would be gratefully received.

Thanks

Docwat

  • The Q1 appears to indicate automotive rating.

  • Hello Colin,

    you are right the Q1 refers to the Q100 automotive qualified device version.
    This also implies a more extensive production testing of the devices, to guarantee the automotive compliance.
    So the non-automotive device version should not be used to replace the automotive part.
    The TMS3705DR seems to be an incomplete device name, as the non-automotive version would have a "G4" instead of "Q1". Also the device revision seems to be missing (refer to device datasheet, chapter 8.2; https://www.ti.com/lit/gpn/tms3705). The date code just reflects the manufacturing date.
    I would recommend to clarify on the exact part name before ordering from the alternative supplier.

    Best regards,
    Andreas.

  • Very many thanks Andreas. Yes I certainly could not determine the revision info from the single D and the device part name is horribly truncated.

    Your advice will be followed in caution.

    Do the date codes translate into meaningful manufacturing dates ?

    Our product started in 2013 simply using a TMS3705A , before the automarket started up and we had nil failures to date with several thousand in use, so I am not particularly worried about the Q100 approval. The supplier is on the T.I. approved list for scarce and end of life parts, so that does not raise alarms but obviously the source and quality of the stock may be questionable.

    Thanks for responding which is extremely helpful.

    Colin Watson

  • Colin,

    by chance I had a discussion with a colleague, which knows the device history from the time before I started at TI.
    It turned out that the TMS3705DR was indeed a valid device before 2004.
    At that time TI just did not reflect the die rev. and the "Q1" status in the device symbolization.
    But it was also automotive qualified material.
    The date codes 0049 amd 0401 are not meaningful according to the today's coding, but maybe they used a different coding before 2004.
    Today only the first 2 digits in the 7 digits lot trace code are reflecting the year and the month.
    Anyway, the parts should be still OK, but you should assume that they are almost 20 years old, which might have an impact on the assembly process.

    Best regards,
    Andreas.

  • Excellent Andreas,

    I will take an interest in the TMS3705DR device package which looks as though it may not be surface mount which would present an assembly challenge.

    I will put that to our assembly shop in  N.H.

    Your research means the device was probably manufactured when I reached retirement age !

    Much appreciated,

    Colin