single lm339

Discussion in 'General Electronics Chat' started by kubeek, Aug 25, 2010.

  1. kubeek

    Thread Starter AAC Fanatic!

    Sep 20, 2005
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    Hi,
    i´m looking for a chip with a single comparator similar to lm339, the most limiting thing is the power supply range from 2V.
    Do you know anything that I could use, or do I just need to stick with the 4pack?
     
  2. tom66

    Senior Member

    May 9, 2009
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    LM311 is a single comparator version of the LM339.
    LM393 is a dual comparator version.

    The LM311 also has another pin the others do not. It connects to the emitter of the transistor. If you're using a circuit designed for an LM339, connect this to the V- pin. Otherwise, it provides a convenient breakout.
     
  3. kubeek

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    OK, i found that LM311 is not the same as 1/4 LM339, because it works only from 5V supply. But the LM393 is the same as 339, and as i am thinking about it i will use it, because a single comparator will be in 8pin package anyway.
     
    Last edited: Aug 27, 2010
  4. SgtWookie

    Expert

    Jul 17, 2007
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    I'm afraid that you have misinterpreted the datasheet.

    It will operate from a single 5v supply rail. However, the absolute maximum differential for an LM311's supply rails is 36v (ref: National Semiconductor datasheet Jan 2001)
    http://www.national.com/ds/LM/LM311.pdf

    You can certainly use an LM193/293/393/2903 dual comparator. Make certain to ground the inputs of the unused half, or you may experience odd problems (high-speed oscillations disturbing the half you are using).
     
  5. kubeek

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    Of course it works with higher supply, but in the OP I stated that I need it to work form 2V supply like the 339 does. Thanks for the help anyway.
     
  6. Wendy

    Moderator

    Mar 24, 2008
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    An LM393 has virtually identical specs, including the 2V power supply. What is the deal?

    Given the package of a LM393 is an 8pin DIP, and would be the same between a single and a dual, there isn't really an advantage for a single comparitors IMO, while the LM393 is directly equivalent to the LM339 other than package layout.
     
  7. kubeek

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    All I wanted to say is that LM311 is not a single comparator version of LM339.
     
  8. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    Here is an overview from National for low power comparators.
    (just remove the .txt, and open in excel).

    Bertus
     
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  9. Papabravo

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    Feb 24, 2006
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  10. Random Blogger

    New Member

    Jun 1, 2017
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    TL331. costs more than LM339 though, but smaller.
     
    Last edited by a moderator: Jun 1, 2017
  11. kubeek

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    Sep 20, 2005
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    Thank you Random Blogger, although after 7 years I don´t even remember what I needed this for, but I guess I somehow solved it anyway :D
     
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  12. crutschow

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    Mar 14, 2008
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    And another newbie necropost. :rolleyes:
     
  13. GopherT

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    Nov 23, 2012
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    I criticized the post last night and I was told newbie necroposts must now be APPROVED by a moderator - this post was approved because of the educational merit. I'm not joking.
     
  14. WBahn

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    Mar 31, 2012
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    It was likely approved because it was on-topic. We used to delete necroposts as a rule unless there was a compelling reason not to, but several established members complained saying that it was too heavy handed and that as long as the new post was on topic that it might stimulate useful further discussion. So the guidance was revised so that necroposts will generally be approved unless they are otherwise in violation, such as hijacking or spamming. As is always the case, you we can't please everyone, so of course now members complain about approving necroposts that are on topic.
     
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  15. GopherT

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    Thank you for the clear explanation of the current policy your team is using.
     
  16. crutschow

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    Mar 14, 2008
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    My only comment is that there should be an indication in the thread listings that it is a necropost, so that we don't go off and running, replying to previous questions in the post without noticing the age of the posts (which I've done a few times :oops:.)
     
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  17. WBahn

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    Mar 31, 2012
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    I recommended that a couple of times even before I became a mod. I think it would be quite useful. Apparently it's not a readily available plug-in, so unless there's an admin up to the programming....

    Once possibility which might be easier is to color code the top bar of a post to reflect it's age. Perhaps make it yellow (at least on the Blue scheme). The new post would still be the new post color, but the prior posts would be highlighted as being old. That would help, though some things would still fall through the crack, such as the new post starting a new page.
     
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