SINGLE/DUAL PRECISION HIGH SPEED MICROPOWER TIMER

GENERAL DESCRIPTION

The ALD1502/ALD2502 timers are high performance single/dual mono-

lithic timing circuits built with advanced silicon gate CMOS technology.

They offer the benefits of high input impedance, thereby allowing smaller

timing capacitors and a longer timing cycle; high speed, with typical cycle

time of 400ns; low power dissipation for battery operated environment;

reduced supply current spikes, allowing smaller and lower cost decoupling

capacitors.

Each timer is capable of producing accurate time delays and oscillations in

both monostable and astable operation, and operates in the one-shot

(monostable) 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 respec-

When the trigger input is below the trigger level, the output is in the high

state and sourcing 2mA. When the 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

• High speed operation -- 2.5MHz typical oscillation at 5V

• High discharge sinking current of 80mA at 5V

• Guaranteed low operating supply voltage of 2V to 12V

• Functional equivalent to and same pin-out as NE555/NE556

with greatly expanded high and low frequency ranges

• High speed, low power, monolithic CMOS technology

• Low supply current 50

µA typical for ALD1502

and100

µA typical for ALD2502

• Extremely low trigger, threshold and reset currents 10pA typical

• Operates in both monostable and astable modes

• Fixed 50% duty cycle or adjustable duty cycle

• CMOS, NMOS and TTL compatible input/output

• Low supply current spikes

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

• Synchronized timer

ALD1502/ALD2502

Operating Temperature Range *

-55

°C to +125°C0°C to +70°C0°C to +70°C

8-Pin

8-Pin Small Outline

8-Pin Plastic Dip

CERDIP Package

Package (SOIC)

Package

ALD1502 DA

ALD1502 SA

ALD1502PA

14-Pin

14-Pin Small Outline 14-Pin Plastic Dip

CERDIP Package

Package (SOIC)

Package

ALD2502 DB

ALD2502 SB

ALD2502 PB

* Contact factory for industrial temperature range

PIN CONFIGURATION

BLOCK DIAGRAM (EACH TIMER)

ORDERING INFORMATION

DSC1

THRES1

CONT1

RST1

OUT1

TRIG1

GND

TRIG2

OUT2

RST2

CONT2

THRES2

DSC2

V+

2

3

4

5

6

7

9

10

11

12

13

14

1

1

2

3

4

8

7

6

5

TOP VIEW

DA, PA, SA PACKAGE

GND

TRIG

OUT

RST

V+

DISC

THRES

CONT

TOP VIEW

DB, PB, SB PACKAGE

8

OUTPUT

(3)

DISCHARGE

(7)

RESET

(4)

R

S

R

R

R

TRIGGER

(2)

GND

(1)

CONTROL

(5)

THRESHOLD

(6)

V+

(8)

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