1 General description
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.
2 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

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