SLVA720A July   2015  – October 2020 CD14538B , CD14538B-MIL , CD4047B , CD4047B-MIL , CD4098B , CD4098B-MIL , CD54HC123 , CD54HC221 , CD54HC4538 , CD54HCT123 , CD54HCT4538 , CD74HC123 , CD74HC221 , CD74HC423 , CD74HC4538 , CD74HC4538-Q1 , CD74HCT123 , CD74HCT221 , CD74HCT423 , CD74HCT4538 , SN54121 , SN54123 , SN54221 , SN54AHC123A , SN54AHCT123A , SN54LS123 , SN54LS123-SP , SN54LS221 , SN74121 , SN74221 , SN74AHC123A , SN74AHC123A-EP , SN74AHCT123A , SN74LS122 , SN74LS123 , SN74LS221 , SN74LS423 , SN74LV123A , SN74LV123A-EP , SN74LV123A-Q1 , SN74LV221A , SN74LV221A-Q1 , SN74LVC1G123

 

  1. 1Introduction
  2. 2Terminology
  3. 3Theory of Operation
    1. 3.1 Basic Concept
    2. 3.2 Operation
  4. 4Applications
    1. 4.1 General Design Considerations
      1. 4.1.1 Pulse Length Determination
        1. 4.1.1.1 Temperature Stability
    2. 4.2 SN74LVC1G123 Applications
      1. 4.2.1 Switch Debounce
        1. 4.2.1.1 Requirements
        2. 4.2.1.2 Schematic
        3. 4.2.1.3 Component Selection
      2. 4.2.2 Leading and Trailing Edge Detector
        1. 4.2.2.1 Requirements
        2. 4.2.2.2 Schematic
        3. 4.2.2.3 Component Selection
  5. 5Frequently Asked Questions
    1. 5.1 How do I calculate the output pulse length?
    2. 5.2 How do I configure the SN74LVC1G123's inputs for ______ edge triggering?
    3. 5.3 How stable is the output pulse length over VCC changes?
    4. 5.4 How stable is the output pulse length over temperature changes?
    5. 5.5 Which inputs of the SN74LVC1G123 have Schmitt-triggers?
    6. 5.6 Can I connect the Cext pin to ground?
  6. 6Revision History

2 Terminology

  • Stable State – The natural, resting, or ‘off’ state of a monostable multivibrator’s output; usually ‘low’
  • Unstable State – The temporary, active, or ‘on’ state of a monostable multivibrator’s output; usually ‘high’
  • Pulse Width – The amount of time for which the output is switched. Often referred to as ‘tw’
  • Trigger – The input signal edge which causes an output pulse to be generated. The trigger can be on a rising or falling edge depending on which input is used.
  • Retrigger – The act of applying a trigger signal while the output of the system is already in the unstable state.
  • Retriggerable - A monostable multivibrator that has the capability to retrigger.