74HC5555; 74HCT5555

Programmable delay timer with oscillator

The 74HC5555 is a precision programmable delay timer which consist of:

  • 24-stage binary counter
  • integrated oscillator (using external timing components)
  • retriggerable/non-retriggerable monostable
  • automatic power-ON reset
  • output control logic
  • oscillator control logic
  • overriding asynchronous master reset (MR).

The 74HC5555 inputs include clamp diodes. This enables the use of current limiting resistors to interface inputs to voltages in excess of VCC.

Features and benefits

  • Supply voltage range from 2.0 V to 6.0 V
  • CMOS input levels
  • Positive and negative edge triggered
  • Retriggerable or non-retriggerable
  • Programmable delay:
    • minimum: 100 ns
    • maximum: depends on input frequency and division ratio
  • Divide-by range of 2 to 224
  • Direct reset terminates output pulse
  • Very low power consumption in triggered start mode
  • 3 oscillator operating modes:
    • RC oscillator
    • Crystal oscillator
    • External oscillator
  • Device is unaffected by variations in temperature and VCC when using an external oscillator
  • Automatic power-ON reset
  • Schmitt trigger action on both trigger inputs
  • Direct drive for a power transistor
  • High precision due to digital timing
  • Complies with JEDEC standard no. 7 A
  • ESD protection:
    • HBM EIA/JESD22-A114A exceeds 2000 V
    • MM EIA/JESD22-A115-A exceeds 200 V
  • Specified from -40 °C to +85 °C and -40 °C to +125 °C


  • Motor control
  • Delay circuits
  • Precision timing
  • Domestic appliances


Type numberProduct statusVCC (V)Output drive capability (mA)Logic switching levelstpd (ns)Power dissipation considerationsTamb (°C)Rth(j-a) (K/W)Ψth(j-top) (K/W)Rth(j-c) (K/W)Package name
74HC5555DProduction2.0 - 6.0- 20/ + 25CMOS89low-40~125641.021SO16


Type numberPackagePackage informationReflow-/Wave solderingPackingStatusMarkingOrderable part number, (Ordering code (12NC))
Reel 13" Q1/T1Active74HC5555D74HC5555D,118
( 9339 985 90118 )
Bulk PackActive74HC5555D74HC5555D,112
( 9339 985 90112 )

Quality, reliability & chemical content

Type numberOrderable part numberChemical contentRoHS / RHFLeadfree conversion dateEFRIFRMTBF (hour)MSLMSL leadfree
74HC5555D74HC5555D,11874HC5555Dweek 4, 200484.96.621.51E811
74HC5555D74HC5555D,11274HC5555Dweek 4, 200484.96.621.51E811
Quality and reliability disclaimer

Documentation (4)

File nameTitleTypeDate
74HC5555Programmable delay timer with oscillatorData sheet2018-07-05
SO-SOJ-REFLOWFootprint for reflow solderingReflow soldering2009-10-08
SO-SOJ-WAVEFootprint for wave solderingWave soldering2009-10-08
SOT109-1plastic, small outline package; 16 leads; 1.27 mm pitch; 9.9 mm x 3.9 mm x 1.35 mm bodyPackage information2020-04-21


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