ALD4501

QUAD PRECISION HIGH SPEED MICROPOWER TIMER

PIN CONFIGURATION

• 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

GENERAL DESCRIPTION

The ALD4501 timer is a high performance QUAD 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; and reduced supply current

spikes allowing smaller and lower cost decoupling capacitors. Each of the

four timers can be independently operated in either the monostable,

astable, or 50% duty cycle mode.

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

both monostable and astable operation.

It 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. All four timers share the same control

and reset pins so that timing functions are synchronized.

FEATURES

• High speed operation -- 2MHz typical oscillation at 5V

• Each discharge output sinking current: 40mA at 5V

• Guaranteed low operating supply voltage of 2 to 12V

• Each timer is functionally equivalent to NE555 with greatly expanded

high and low frequency ranges

• High speed, low power, monolithic CMOS technology

• Low supply current 150

µA typical

• 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

BLOCK DIAGRAM (EACH TIMER)

Operating Temperature Range *

-55

°C to +125°C0°C to +70°C0°C to +70°C

20-Pin

20-Pin

20-Pin

CERDIP

Small Outline

Plastic Dip

Package

Package (SOIC)

Package

ALD4501 DE

ALD4501 SE

ALD4501 PE

ORDERING INFORMATION

* Contact factory for industrial temperature range

DE, PE, SE PACKAGE

CONT

RST

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

OUTPUT

DISCHARGE

RESET

R

S

R

R

R

TRIGGER

CONTROL

THRESHOLD

V+

V-

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