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LM139AQML: LM139J/883 vs LM139JB

Davide Garofalo
Prodigy 10 points
Part Number: LM139AQML

What is the difference between LM139J/883 and LM139JB?  I used LM139JB 10 times and had random failures occurring.  when I replaced that part with LM139J/883 it now works 100% of the time on 10 boards.  That was the only change.  

There seems to be differences in propagation delay, offset voltage/current (while looking at the datasheets).  They are both under SMD 5962-87739.  I would like some confidence to think that although they are both QML parts, their minor differences could result in different behavior given a certain design constraint/condition.  

  • 0
    TI__Guru 52986 points

    Hello Davide,

    The biggest difference is that they are two different devices from two different companies (at the time) on two different processes.

    The LM139J/883 is the ex-National Semiconductor device (and still manufactured under the NSC process).

    The LM139JB is the native Texas Instruments device.

    Both meet the basic SMD specifications, but will have differences in the operational extremes.

    What is failing?

  • 0
    Prodigy 10 points

    There is a signal decaying from about 9V  to 0V in 100 uS, and we want the comparator state to change when compared to a threshold.  The output changing state is crossed with a "timer."  If the crossover does not happen at the right time, we fail the test.  Its looking like a timing issue and we are too close to a margin.  

  • 0 in reply to Davide Garofalo
    TI__Guru 52986 points

    Hello Davide,

    What are the supply voltages and threshold voltage? Are there any "filter" caps on the inputs or output? If you are violating the input range, the response time can be negatively affected.

    Can you send a schematic and, possibly, a scope photo?

    I can reach out to you via your registered email if you do not wish to post the info publicly.

  • 0 in reply to Paul Grohe
    TI__Mastermind 24310 points

    Davide

    I am closing the thread because there has been no new post in a while.  If further support is required, please reply or feel free to open a new post.

    Thanks

    Chuck