FEATURES
· 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
· Low power consumption in active
mode with respect to TTL type
timers
· High precision due to digital timing
· Output capability: 20 mA
· ICC category: MSI.
APPLICATIONS
· Motor control
· Attic fan timers
· Delay circuits
· Automotive applications
· Precision timing
· Domestic appliances.

GENERAL DESCRIPTION
The 74HC/HCT5555 are high-speed
Si-gate CMOS devices and are pin
compatible with low power Schottky
TTL (LSTTL). They are specified in
compliance with JEDEC standard
no. 7A.
The 74HC/HCT5555 are precision
programmable delay timers 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).