Manual Reset IC

Discussion in 'General Electronics Chat' started by crazyengineer, Sep 20, 2013.

  1. crazyengineer

    Thread Starter Member

    Dec 29, 2010
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    Hello everyone. I'm looking for an IC in which when I apply 5v to it, the chip's output will go open drain for 15s-20s. I tried looking at watchdog timers, but they require pulses for it to time out. Does anyone have any suggestions on IC's that can do this?
     
  2. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    Why not just a transistor or mosfet?
     
  3. crazyengineer

    Thread Starter Member

    Dec 29, 2010
    156
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    I would use a mosfet, but I'm afraid I will have limited space to work with.
     
  4. #12

    Expert

    Nov 30, 2010
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    You are looking for something smaller than a single transistor? That will be difficult. How small do you need this to be?
     
  5. MrChips

    Moderator

    Oct 2, 2009
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    You need a power-on reset circuit, something like a MAX823, MAX824, MAX825

    15-20 seconds is unusually long.
     
  6. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    Bigger than a transistor/mosfet though.. So if thats truly a requirement then he is out of luck..
     
  7. ian field

    Distinguished Member

    Oct 27, 2012
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    Mitsubishi used to do power on reset chips - I think their semiconductor division became part of Renaiaance along with that of Hitachi.
     
  8. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    You are looking for what's called a power supervisor. They are ubiquitous and packages in 3 lead transistor packages (sorry, all I see are SMD so they are incredibly tiny.

    Linkie
     
  9. ian field

    Distinguished Member

    Oct 27, 2012
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    Some PC ATX PSUs have a dedicated chip for the power good line, but I can't remember if they're the same thing or not.

    Even recently, I've found 5-pin SIL types as opposed to microscopic SMD.
     
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