SCEA094 October   2020 SN74AUP1G17 , SN74LVC1G17 , SN74LVC1G17-Q1


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  2.   Design Considerations
  3.   Recommended Parts

Design Considerations

  • Select a time constant based on the bouncing characteristics of your switch
  • Select a resistor based on power consumption, input voltage, or capacitor size limitations
    • Power consumption is calculated with the pullup voltage and resistor value: P = V2 ÷ R
    • Input voltage is determined by voltage drop across the resistor caused by leakage into the device input. This is calculated with Ohm's Law: V = I × R
    • Capacitor values can be limited due to package size
Time Constants for Common Resistor and Capacitor Values
Capacitor (μF)Time Constant (ms)(1)
R = 10 kΩR = 100 kΩR = 1 MΩ
Time constant should be approximately half of the desired debounce time. This is commonly selected as 10 ms to give maximum debounce time while preventing humans from noticing the delay.