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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    Sep 20, 2005
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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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    Sep 20, 2005
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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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    Sep 20, 2005
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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
     
    kubeek likes this.
  9. Papabravo

    Expert

    Feb 24, 2006
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