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TMP122 Revision Differences

Stefan Rager
Prodigy 60 points
Other Parts Discussed in Thread: TMP122, TMP112

Hello.

We are using the TMP122 for years and it has been a reliable solution. The typical temperature deviation is below 0.5°C, however within the last batch we have a cut. The first part is as usual whereas the second part gives temperatures that are 1.25°C higher in average and the deviation is about 0.8°C. We do not reference the absolute temperature but we compare the parts to each other.

Our pcbs are manufactured from another company but they could trace that they changed the reel within this last batch.

On TI's TMP122 page are no errata files listed however we found that there are PCNs. Most likely the parts from the new reel are Rev.A as they were purchased in march 2014. I found out from the PCNs that the changes made in Rev.A are cancelled with Rev.B but there are no reasons mentioned.

Do you suspect that this correllates or is this just random? Can you give me more information about the revisions?

Thank you.

Stefan

  • 0
    TI__Genius 15760 points

    Hi Stefan,

    Thanks for using TI E2E forums. Let me find more information about Rev A and B. I will get back to you soon.

    Mayrim

  • 0 in reply to Mayrim Verdejo
    TI__Genius 15760 points

    Hi Stefan,

    There are multiple packages, which one are you using? 

    Mayrim

  • 0 in reply to Mayrim Verdejo
    Prodigy 60 points

    Hi Mayrim,

    Thank you for your help.
    We are using the 6 pin SOT-23 package. The manufacturer told me that he purchased a reel that contains 3000 items. Therefore it must be either TMP122AIDBVR or TMP122AIDBVRG4. I could not find out the difference between those.

    Regards,

    Stefan

  • 0 in reply to Stefan Rager
    TI__Genius 15760 points

    Hi Stefan,

    I did research all the changes applied to the TMP112AIDBVR and TMP122AIDBVRG4 for the last 4 years period. There is only one PCNs issued but it was cancelled. The proposed change was never implemented on the part. 

    Why there are 2 revisions? I am not seeing on the PCN system any reason or request for new revisions. The two revisions should be the same. Every change applied to our parts is logged in a "Change Log" system and there is no change log on the system.

    In this case you are seeing 1.25C offset, the datasheet spec is at 1.5C. I believe the lot you received is close to the limits. When offloads/BOM changes are being worked on, there are some slight shifts (not a whole lot), we perform characterization to verify that the device performs to PDS spec across the temp range. But differences in material is unavoidable esp with Fab changes. 

    Hope this help!

    Mayrim

  • 0 in reply to Mayrim Verdejo
    Prodigy 60 points

    Hi Mayrim,

    Thank you for the information. This helps a lot. Maybe we should have a look on the TMP112 to achieve higher accuracy.

    Stefan

  • 0 in reply to Stefan Rager
    TI__Genius 15760 points

    Hi Stefan,

    I did not know that using another device was an option. In this case TMP112 can be a good replacement. The TMP112 device offers an accuracy of ±0.5°C without requiring calibration or external component signal conditioning. It also have calibrating feature that allows you to calibrate for an accuracy as good as ±0.17°C. 

    Let me know how it goes!

    Best Regards,

    Mayrim