Allegro A5347CA Datasheet

TIMER START

I / O

LOW-V SET

TIMER OUT

LED

+ SUPPLY

TIMING RES.

FEEDBACK

5347

WITH INTERCONNECT AND TIMER

required features for an ionization-type smoke detector. A networking

1

2

3

4

5

6

7

89

LOGIC

OSC. &
TIMING

V

DD

HORN

DRIVER

16

GUARD

2

15

DETECT. IN

14

GUARD

1

SENSITIVITY

13

SET

12

OSC. CAP.

11

HORN

2

10

HORN

1

V

– SUPPLY

SS

capability allows as many as 125 units to be interconnected so that if
any unit senses smoke, all units will sound an alarm. In addition,
special features are incorporated to facilitate alignment and test of the
finished smoke detector. This device is designed to comply with
Underwriters Laboratories Specification UL217.

a minimum by powering down the device for 1.66 seconds and sensing
smoke for only 10 ms. Every 24 on/off cycles, a check is made for low
battery condition. By substituting other types of sensors, or a switch
for the ionization detector, this very-low power device can be used in
numerous other battery-operated safety/security applications.

Data Sheet

26110.2

SMOKE DETECTOR

The A5347CA is a low-current, CMOS circuit providing all of the

The internal oscillator and timing circuitry keeps standby power to

Dwg. PC-004

ABSOLUTE MAXIMUM RATINGS

(Voltages are referenced to VSS)

Supply Voltage Range,

VDD................................ -0.5 V to +15 V

Input Voltage Range,

V

........................ -0.3 V to V

IN

Input Current, I

............................... 10 mA

IN

Operating Temperature Range,

T

..................................... 0°C to +50°C

A

Storage Temperature Range,

T

............................... -55°C to +125°C

S

CAUTION: CMOS devices have input static
protection but are susceptible to damage when
exposed to extremely high static electrical
charges.

+ 0.3 V

DD

The A5347CA is supplied in a low-cost, 16-pin dual in-line plastic
package. It is rated for continuous operation over the temperature
range of 0°C to +50°C.

FEATURES

■ Interconnect Up to 125 Detectors

■ Piezoelectric Horn Driver

■ Guard Outputs for Detector Input

■ Pulse Testing for Low Battery

■ Power-ON Reset

■ Internal Timer & Control for Reduced Sensitivity

■ Built-In Hysteresis Reduces False Triggering

Always order by complete part number: A5347CA .

5347

SMOKE DETECTOR
with INTERCONNECT
and TIMER

FUNCTIONAL BLOCK DIAGRAM AND TYPICAL APPLICATION

+ SUPPLY

9 V

3

LOW-V

SET

13

SENSITIVITY

SET

– SUPPLY

9

V

SS

V

DD

6

–
+

+
–

+
–

14 15 16

GUARD GUARD

DETECT.

IN

12

I / O

2

LOGIC

V

DD

POWER-ON

OSCILLATOR

& TIMING

RESET

1

TIMER

START

FEEDBACK

8

11

HORN

2

10

HORN

1

5

LED

TIMING RES.

7

OSC. CAP.

12

4

TIMER OUT

+V

+V

115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]
Copyright © 1995, Allegro MicroSystems, Inc.

Dwg. FC-001-2

5347

SMOKE DETECTOR
with INTERCONNECT
and TIMER

ELECTRICAL CHARACTERISTICS at T

R

= 8.2 MΩ (unless otherwise noted).

7

Characteristic Pin Test Conditions Min. Typ. Max. Units

Supply Voltage Range 6 Operating 6.0 9.0 12 V
Detector Input Current 15 0 to 40% RH, V
Input Offset Voltage 14-15 Active Guard — — ±100 mV

Hysteresis 13 No Alarm to Alarm 90 130 170 mV
Common Mode Range 14-15 Guard Amplifier 2.0 — V

Active Guard Impedance 14 to V

Oscillator Period 12 No Alarm 1.34 1.67 2.00 s

Oscillator Pulse Width 4 8.0 10 12 ms

Test

16-15 Active Guard — — ±100 mV
15-13 Detect Comparator — — ±50 mV

13-15 Smoke Comparator 0.5 — V

16 to V

= +25°C, V

A

SS
SS

Alarm 32 40 48 ms

= 9.0 V, VSS = 0 V, C

DD

= 0 to 9.0 V — — ±1.0 pA

IN

—10—kΩ
— 500 — kΩ

= 0.1 µF,

12

Limits

DD
DD

- 0.5 V

- 2.0 V

Timer Period 4 After Pin 1 High-to-Low, No Smoke 8.0 10 12 min
Low Voltage Threshold 6 T
Sensitivity Adj. Voltage 13 V
Horn Output Voltage 10-11 I

Horn Output ON Time 10-11 Alarm 120 160 208 ms

Horn Output OFF Time 10-11 Alarm 60 80 104 ms

Timer Start Logic Levels 1 V

Timer Start Input Current 1 V

NOTE 1: Negative current is defined as coming out of (sourcing) the specified device pin.
NOTE 2: Alarm (Smoke) Condition is defined as V

< V

; No Alarm (No Smoke) Condition as V15 > V13.

15

13

= 0 to 50°C 7.2 — 7.8 V

A

, pin 13 open circuit 48.5 50 51.5 %

13/VDD

= 16 mA, VDD = 9.0 V — 0.1 0.5 V

OUT

= 16 mA, VDD = 7.2 V — — 0.9 V

I

OUT

= -16 mA, VDD = 9.0 V 8.5 8.8 — V

I

OUT

= -16 mA, VDD = 7.2 V 6.3 — — V

I

OUT

Low Battery 8.0 10 12 ms

Low Battery 32 40 48 s

IH

V

IL

= 9.0 V 20 — 80 µA

IN

3.5 — — V
— — 1.5 V

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