Does anyone know of a small IC package for a "momentary latch"?

Discussion in 'General Electronics Chat' started by durable126, Feb 28, 2016.

  1. durable126

    Thread Starter Member

    Feb 20, 2016
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    Does anyone know of a small ic package for a momentary latch?

    For a momentary switch to turn something on and off

    I know how to use one using bits, but would rather not have the headache

    I have not found any ready made IC out there but I'm sure someone makes one.
    anyone know of any?
     
  2. durable126

    Thread Starter Member

    Feb 20, 2016
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    I should clarify, small meaning 8 pin dip package area, does not need to be smt
     
  3. ian field

    Distinguished Member

    Oct 27, 2012
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    A momentary latch AKA: a monostable - you can make that with a555.
     
  4. durable126

    Thread Starter Member

    Feb 20, 2016
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    a latch for a pushbutton switch to turn something on and off
    as opposed to a slider or toggle switch
     
  5. ian field

    Distinguished Member

    Oct 27, 2012
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    That's a bistable, some manufacturers are producing individually packaged logic gates - there may also be individual flip-flop logic elements.

    Or you could use 2 transistors and a handful of components.
     
  6. durable126

    Thread Starter Member

    Feb 20, 2016
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    That is true but i was trying to avoid having so many parts
     
  7. Papabravo

    Expert

    Feb 24, 2006
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    I don't think such a part exists. AFAIK there have been very few new MSI IC's introduced since the late 1980's. Everything now is FPGA and microprocessors. So how about an 8-pin ATTiny and a few lines of code?
     
  8. absf

    Senior Member

    Dec 29, 2010
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    If you dont mind SMD package, there is at least one....
     
  9. Lindembruck

    Member

    Feb 28, 2016
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  10. Lindembruck

    Member

    Feb 28, 2016
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  11. pebe

    AAC Fanatic!

    Oct 11, 2004
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    As Ian suggested, use a 555.

    Connect pins 2&6 together. Fit a 10k resistor between those pins and V+.; that keeps the latch normally off.
    Connect a momentary push button between pins 2&6 to V-.. The latch will turn on for as long as the button is pressed.
     
  12. AnalogKid

    Distinguished Member

    Aug 1, 2013
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    To turn a momentary pushbutton switch into an alternate-action function, you need a little debouncing and a toggle flipflop. Depending on the circuit voltage, you can use 7400 series TTL or 4000 series CMOS 14-pin chips. With the CD4013 you get two toggle flipflops in one package. There are specialized ICs for LED flashlights that are a single toggle ff in one SMT package, but you usually have to buy a large quantity.

    ak
     
  13. Lindembruck

    Member

    Feb 28, 2016
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    The NC7SV74 pdf linked above looks be what do you want!
     
  14. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    There is even a smaller one 1G80.

    Bertus
     
    AnalogKid and absf like this.
  15. BillB3857

    Senior Member

    Feb 28, 2009
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    ErnieM and Lindembruck like this.
  16. TheButtonThief

    Active Member

    Feb 26, 2011
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    Maybe the OP has a specific switch/button that they would like to use and so switching function needs to be designed.

    My choice would be to use a µc, the ATtiny85 is an 8 pin package and is also available in SMT. The regular package is the same as a 555 but wouldn't require any external components, just an embedded programme.
     
  17. ian field

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    Oct 27, 2012
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    That's the sort of thing I was thinking of.

    Just wire not-Q back to the D input and the output changes state on every CP transition.
     
  18. durable126

    Thread Starter Member

    Feb 20, 2016
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  19. Lindembruck

    Member

    Feb 28, 2016
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    Hi!
    In this link, we have a lot circuits.
    I think, you will can use a Darlington in the flip flop output with a resistor but you need to upload pictures and the flip flop you have with the schematic you has tried.
     
  20. AnalogKid

    Distinguished Member

    Aug 1, 2013
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