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).