Operating Temperature Range *

-55

°C to +125°C0°C to +70°C0°C to +70°C

8-Pin

8-Pin

8-Pin

CERDIP

Small Outline

Plastic Dip

Package

Package (SOIC)

Package

ALD555 DA

ALD555 SA

ALD555 PA

APPLICATIONS

•

High speed one-shot (monostable)

pulse generation

• Precision timing

• Sequential timing

• Long delay timer

• Pulse width and pulse position

modulation

• Missing pulse detector

• Frequency divider

ALD555

HIGH SPEED CMOS TIMER

GENERAL DESCRIPTION

The ALD555 timer is a high performance monolithic timing circuit built with

advanced silicon gate CMOS technology. It offers the benefits of high

input impedance, thereby allowing smaller timing capacitors and longer

timing cycle; high speed, with typical cycle time of 500ns; low power

dissipation for battery operated environment; reduced supply current

spikes, allowing smaller and lower cost decoupling capacitors. It is

capable of producing accurate time delays and oscillations in both

monostable and astable operation. It operates in the one-shot (mono-

stable) mode or 50% duty cycle free running oscillation mode with a single

resistor and one capacitor. The inputs and outputs are fully compatible

with CMOS, NMOS or TTL logic.

There are three matched internal resistors (approximately 200K

Ω each)

that set the threshold and trigger levels at two-thirds and one-third

respectively of V+

.

These levels can be adjusted by using the control

terminal (pin 5). When the trigger input is below the trigger level, the

output is in the high state and sourcing 2mA. When threshold input is

above the threshold level at the same time the trigger input is above the

trigger level, the internal flip-flop is reset, the output goes to the low state

and sinks up to 10mA. The reset input overrides all other inputs and when

it is active (reset voltage less than 1V), the output is in the low state.

FEATURES

• Functional equivalent to NE555 with greatly expanded high

and low frequency ranges

• High speed, low power, monolithic CMOS technology

• Low supply current 100

• Extremely low trigger, threshold and reset currents -- 1pA typical

• High speed operation -- 2MHz oscillation

• Low operating supply voltage 2 to 12V

• Operates in both monostable and astable modes

• Fixed 50% duty cycle or adjustable duty cycle

CMOS, NMOS and TTL compatible input/output

• High discharge sinking current (80mA)

• Low supply current spikes

PIN CONFIGURATION

BLOCK DIAGRAM

GROUND

TRIGGER

OUTPUT

RESET

TOP VIEW

DA, PA, SA PACKAGE

DISCHARGE

THRESHOLD

7

CONTROL

3

1

2

4

6

8

5

OUTPUT

(3)

DISCHARGE

(7)

RESET

(4)

R

S

R

R

R

TRIGGER

(2)

GND

(1)

CONTROL

(5)

THRESHOLD

(6)

V+

(8)

ORDERING INFORMATION

* Contact factory for industrial temperature range

© 1998 Advanced Linear Devices, Inc. 415 Tasman Drive, Sunnyvale, California 94089 -1706 Tel: (408) 747-1155 Fax: (408) 747-1286 http://www.aldinc.com