5364

SMOKE DETECTOR

WITH

INTERCONNECT

www.allegromicro.com

19 CLOCK CYCLES

1.67 s

NO ALARM

NO LOW BATTERY

STANDBY MODE

10 ms

40 ms

24 CLOCK CYCLES

V15 > V13 (NO SMOKE)

V15 < V13 (SMOKE)

V12

OSC. CAP

INTERNAL

CLOCK

LED

SMOKE

COMPARATOR

SMOKE

CHAMBER

HORN

SAMPLE

ALARM

NO LOW BATTERY

30 CLOCK CYCLES

LOW BATTERY

WARNING

HORN

ON TIME

"A"

ALARM AND

LOW BATTERY

NO ALARM

LOW BATTERY

Dwg. WC-003-3

24 CLOCK CYCLES

LED OFF

LED

ON

12 CLOCK

CYCLES

12 CLOCK

CYCLES

36 CLOCK CYCLES

HORN

OFF TIME

"B"

13 CLOCK

CYCLES

24 CLOCK CYCLES

73 CLOCK CYCLES

I/O

SHADED AND UNSHADED AREAS

ARE DIFFERENT TIME SCALES

HORN OFF TIME

"C"

I/O. A connection is provided at pin 2 to

allow multiple smoke detectors to be

commoned. If any single unit detects smoke

(I/O is driven high), all connected units will

sound their associated horns after a nominal 3

second delay. The LED is suppressed when

an alarm is signaled from an interconnected

unit.

Testing. On power up, all internal counters

are reset. Internal test circuitry allows for

low battery check by holding pins 8 and 12

low during power up, then reducing V

monitoring HORN

tests can be accelerated by driving pin 12

with a 2 kHz square wave. The 10 ms strobe

period must be maintained for proper opera-

tion of the comparator circuitry.

TYPICAL APPLICATION

TO

OTHER

UNITS

NOTE

1

NOTE

2

1

2

3

4

5

6

7

89

10

11

12

13

14

15

16

LOGIC

OSC. &

TIMING

HORN

DRIVER

Dwg. EC-005-4

9 V

PUSH

TO

TEST

200 k

Ω

200

Ω

8.2 M

Ω

1

µF

0.1

µF

0.001

µF

330

Ω

NC

NC

NOTE 1: Use an external resistor to adjust sensitivity for a particular smoke

chamber.

NOTE 2: A resistor to ground or V

battery voltage threshold.

TIMING DIAGRAM IN TYPICAL APPLICATION