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LMV721-N: Different Manufacture year, Different Character???

Wei Po Tsai
Prodigy 30 points
Part Number: LMV721-N

Our company has bought a lot of LMV721M5 on 2007. And recently bought the replacement one: LMV721M5/NOPB (Because LMV721M5 is about to obsolete).

Although the character in datasheet is completely the same, in actual test, we mounted LMV721M5 and LMV721M5/NOPB on the same place to the same board. The output is 3.28V with LMV721M5; While the output is 3.10V with LMV721M5/NOPB. 

What might be the reason causing this different characters??? ((We have used different lot number of LMV721M5 and LMV721M5/NOPB to test, and it all get the same result. So We could exclude the possibility that cause by different lot))

  • 0
    TI__Mastermind 22825 points
    Hello Wei,
    Looking at your schematic, the DC voltage at LMV721-N output should be 1.6V (not 3.1 or 3.28V). Unless you are referring to the voltage at C2 (right hand side) plate which is dictated by whatever circuitry it is connected to.
    Please clarify.
    What is the value of R4 and other components?

    Regards,
    Hooman
  • 0 in reply to Hooman Hashemi
    Prodigy 30 points

    Hi! Hooman,

    Thank you for your kindly reply. The schematic is only show the reference presentation. It's not our original schematic due to some NDA reason.

    We will continue to use this IC in the future. But We have to persuade our customers why the output is different when using the same IC which made in different year.

    Besides, We found that there is  difference marking on underside of IC. What is the marking means? is it related to the issue above?

      

    best regard

    Wei-Po 2017/3/31

  • 0 in reply to Wei Po Tsai
    TI__Mastermind 22825 points

    Hi Wei-Po,

    If it helps, you could share your specific schematic with me by email so that we can make sure the difference in output voltage you're measuring is not related to the circuit:

    hooman.hashemi@ti.com

    I'm going to ask around to find out what the markings indicate and whether they are significant?

    I'll get back to you.

    Regards,

    Hooman

  • 0 in reply to Wei Po Tsai
    TI__Guru*** 140126 points
    Wei-Po,

    The bottom three characters define (in order) Year, Month, Last character in lot code per the build instructions for both part numbers.
    However, the decoding process is unknown to me.