A5367 - Allegro MicroSystems, Inc.

SMOKE DETECT OR

WITH INTERCONNECT AND TIMER

The A5367CA is a low-current, CMOS circuit providing all of the

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

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.

The internal oscillator and timing circuitry keeps standby power to

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.

The A5367CA 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 Reverse Battery Protection

■Internal Timer & Control for Reduced Sensitivity

■Built-In Hysteresis Reduces False Triggering

■Temporal Horn Pattern

Always order by complete part number: A5367CA .

Data Sheet

26110.9*

ABSOLUTE MAXIMUM RATINGS

(Voltages are referenced to VSS)

Supply Voltage Range,

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

Reverse Battery (10.5 V) ....................... 20 s

Input Voltage Range,

VIN ........................ -0.3 V to VDD + 0.3 V

Input Current, IIN ............................... 10 mA

Operating Temperature Range,

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

Storage Temperature Range,

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

CAUTION: CMOS devices have input static

protection but are susceptible to damage when

exposed to extremely high static electrical

charges.

LOGIC

OSC. &

TIMING

HORN

DRIVER

GUARD

DETECT. IN

GUARD

SENSITIVITY

SET

OSC. CAP.

HORN

– SUPPLY

TIMER START

I / O

LOW-V SET

TIMER OUT

LED

+ SUPPLY

TIMING RES.

FEEDBACK

Dwg. PC-004

5367

The selectable Hush Feature may be covered

by U.S. patent number Re. 33,920. Any sale or

use of the Hush Feature in a smoke alarm in

the U.S. would be a possible infringement of

this patent.

5367

SMOKE DETECTOR

WITH INTERCONNECT

AND TIMER

115 Northeast Cutoff, Box 15036

Worcester, Massachusetts 01615-0036 (508) 853-5000

FUNCTIONAL BLOCK DIAGRAM AND TYPICAL APPLICATION

9 V

LOW-V

SET

– SUPPLY

+ SUPPLY I / O

TIMING RES.

FEEDBACK

DETECT.

OSC. CAP.

POWER-ON

RESET

OSCILLATOR

& TIMING

LOGIC

SENSITIVITY

SET

–

GUARD GUARD

HORN1

HORN2

LED

TIMER OUT

TIMER

START

VDD

14 15 16

VDD

VSS

Dwg. FC-001B

5367

SMOKE DETECTOR

WITH INTERCONNECT

AND TIMER

www.allegromicro.com

Test Limits

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, VIN = 0 to 9.0 V — — ±1.0 pA

Input Offset Voltage 14-15 Active Guard — — ±100 mV

16-15 Active Guard — — ±100 mV

15-13 Detect Comparator — — ±50 mV

Hysteresis 13 No Alarm to Alarm 90 130 170 mV

Common Mode Range 14-15 Guard Amplifier 2.0 — VDD - 0.5 V

13-15 Smoke Comparator 0.5 — VDD - 2.0 V

Active Guard Impedance 14 to VSS —10—kΩ

16 to VSS — 500 — kΩ

Oscillator Period 12 No Alarm 1.34 1.67 2.00 s

Alarm 32 40 48 ms

Oscillator Pulse Width 4 8.0 10 12 ms

Timer Period 4 After Pin 1 High-to-Low, No Smoke 8.0 10 12 min

Low Voltage Threshold 6 TA = 0 to 50°C 7.2 — 7.8 V

Sensitivity Adj. Voltage 13 V13/VDD, pin 13 open circuit 48.5 50 51.5 %

Horn Output Voltage 10-11 IOUT = 16 mA, VDD = 9.0 V — 0.1 0.5 V

IOUT = 16 mA, VDD = 7.2 V — — 0.9 V

IOUT = -16 mA, VDD = 9.0 V 8.5 8.8 — V

IOUT = -16 mA, VDD = 7.2 V 6.3 — — V

Horn Output ON Time 10-11 Alarm (see figure, time “A”) 450 500 550 ms

Low Battery 8.0 10 12 ms

Horn Output OFF Time 10-11 Alarm (see figure, time “B”) 450 500 550 ms

Alarm (see figure, time “C”) 1350 1500 1650 ms

Low Battery 32 40 48 s

Timer Start Logic Levels 1 VIH 4.5 — — V

VIL — — 2.5 V

Continued next page . . .

ELECTRICAL CHARACTERISTICS at TA = +25°C, VDD = 9.0 V, VSS = 0 V, C12 = 0.1 µF,

R7 = 8.2 MΩ (unless otherwise noted).

NOTE 1: Negative current is defined as coming out of (sourcing) the specified device pin.

NOTE 2: Alarm (Smoke) Condition is defined as V15 < V13; No Alarm (No Smoke) Condition as V15 > V13.

5367

SMOKE DETECTOR

WITH INTERCONNECT

AND TIMER

115 Northeast Cutoff, Box 15036

Worcester, Massachusetts 01615-0036 (508) 853-5000

Timer Start Input Current 1 VIN = 9.0 V 20 — 80 µA

Timer Out Output Current 4 VOUT = 0.5 V 500 — — µA

LED Output ON Current 5 VDD = 7.2 V, VOUT = 1.0 V 10 — — mA

LED Output ON Time 5 No Local Alarm; Not Latched 8.0 10 12 ms

LED Output OFF Time 5 No Alarm, In Standby 32 40 48 s

No Alarm, Timer Mode 8.0 10 12 s

I/O Current 2 No Alarm, VI/O = VDD - 2.0 V 25 — 60 µA

Alarm, VI/O = VDD - 2.0 V -7.5 — — mA

Charge Dump, VI/O = 1.0 V 5.0 — — mA

I/O Charge Dump Duration 2 After Local Alarm or Test 1.33 1.66 1.99 s

I/O Alarm Voltage 2 External “Alarm” In 3.0 — — V

I/O Delay 2 “Alarm” Out — 3.0 — s

Supply Current 6 VDD = 9.0 V, No Alarm, No Loads — 5.0 9.0 µA

VDD = 12 V, No Alarm, No Loads — — 12 µA

Test Limits

Characteristic Pin Test Conditions Min. Typ. Max. Units

ELECTRICAL CHARACTERISTICS continued

NOTE 1: Negative current is defined as coming out of (sourcing) the specified device pin.

NOTE 2: Alarm (Smoke) Condition is defined as V15 < V13; No Alarm (No Smoke) Condition as V15 > V13.

CIRCUIT DESCRIPTION

The A5367CA is a low-current CMOS circuit

providing all of the required features for an

ionization-type smoke detector.

Oscillator. An internal oscillator operates

with a period of 1.67 seconds during no-

smoke conditions. Every 1.67 seconds,

internal power is applied to the entire circuit

and a check is made for smoke. Every 24

clock cycles (40 seconds), the LED is pulsed

and a check is made for low battery by

comparing VDD to an internal reference.

Since very-low currents are used in the

device, the oscillator capacitor at pin 12

should be a low-leakage type (PTFE, polysty-

rene, or polypropylene).

Detector Circuitry. When smoke is detected, the resistor divider

network that sets the sensitivity (smoke trip point) is altered to increase

the sensitivity set voltage (pin 13) by typically 130 mV with no exter-

nal connections to pins 3 or 13. This provides hysteresis and reduces

false triggering. An active guard is provided on both pins adjacent to

the detector input (pin 15). The voltage at pins 14 and 16 will be

within 100 mV of the input. This will keep surface leakage currents to

a minimum and provide a method of measuring the input voltage

without loading the ionization chamber. The active guard amplifier is

not power strobed and thus provides constant protection from surface

leakage currents. The detector input has internal diode protection

against static damage.

Alarm Circuitry. If smoke is detected, the oscillator period changes

to 40 ms and the horn is enabled. The horn output is typically 0.5 s

ON, 0.5 s OFF, 0.5 s ON, 0.5 s OFF, 0.5 s ON, 1.5 s OFF (temporal

horn pattern). During the OFF time, smoke is checked and will inhibit

further alarm output if smoke is not sensed. During smoke conditions

the low battery alarm is inhibited and the LED is driven at a 1 Hz rate.

5367

SMOKE DETECTOR

WITH INTERCONNECT

AND TIMER

www.allegromicro.com

TYPICAL APPLICATION

Sensitivity Adjust. The detector sensitiv-

ity to smoke is set internally by a voltage

divider connected between VDD and VSS. The

sensitivity can be externally adjusted to the

individual characteristics of the ionization

chamber by connecting a resistor between pin

13 and VDD, or between pin 13 and VSS.

Low Battery. The low battery threshold is

set internally by a voltage divider connected

between VDD and VSS. The threshold can be

increased by connecting a resistor between

pin 3 and VDD. The threshold can be de-

creased by connecting a resistor between pin

3 and VSS. The battery voltage level is

checked every 40 seconds during the 10 mA,

10 ms LED pulse. If an LED is not used, it

should be replaced with an equivalent resistor

(typically 500 Ω to 1000 Ω) such that the

battery loading remains at 10 mA.

Timer. An internal timer is provided that

can be used in various configurations to allow

for a period of reduced smoke detector

sensitivity (“hush”). When a high-to-low

transition occurs at pin 1, the internal timer is

reset, the timer mode enabled, and the circuit

reset to a no alarm condition. The LED will

flash at a 10 second rate. If the level of

smoke is increased such that the reduced

sensitivity level is reached, the device will go

into the alarm condition. The timer, how-

ever, will continue to completion of the

nominal 10-1/4 minute period (368 clock

cycles). If the timer mode is not used, pin 1

should be tied low.

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

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

chamber.

NOTE 2: Select resistor to reduce sensitivity during timer mode.

NOTE 3: A resistor to ground or VDD may be added to this pin to modify low

battery voltage threshold.

TIMER

MODE

OTHER

UNITS

NOTE

LOGIC

OSC. &

TIMING

HORN

DRIVER

Dwg. EC-005A

9 V

NOTE 2

200 kΩ

50 kΩ

200 kΩ

200 Ω

8.2 MΩ

1 µF

0.1 µF

1 MΩ

200 kΩ

PUSH

TEST

0.001 µF

330 Ω

unit. An internal NMOS device acts as a charge dump to aid in appli-

cations involving a large (distributed) capacitance on pin 2. The

charge dump is activated only on the removal of a local alarm.

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 VDD and monitoring HORN1 (pin 10).

All functional tests can be accelerated by driving pin 12 with a 2 kHz

square wave. The 10 ms strobe period must be maintained for proper

operation of the comparator circuitry.

5367

SMOKE DETECTOR

WITH INTERCONNECT

AND TIMER

115 Northeast Cutoff, Box 15036

Worcester, Massachusetts 01615-0036 (508) 853-5000

TIMING DIAGRAMS IN TYPICAL APPLICATION

NON-TIMER MODE

TIMER MODE

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-003-2

24 CLOCK CYCLES

LED OFF

LED

12 CLOCK

CYCLES 12 CLOCK

CYCLES 36 CLOCK CYCLES

HORN

OFF TIME

"B"

13 CLOCK

CYCLES

24 CLOCK CYCLES

73 CLOCK CYCLES

I/O

I/O CHARGE DUMP

SHADED AND UNSHADED AREAS

ARE DIFFERENT TIME SCALES

HORN OFF TIME

"C"

1.67 s 10 ms

V12

OSC. CAP

INTERNAL

CLOCK

LED

HORN

Dwg. WC-005-2

LED

TIMER

START

TIMER

OUT

6 CLOCK CYCLES

368 CLOCK CYCLES

OUTPUTS OFF (HIGH Z)

I/O CHARGE DUMP

I/O

5367

SMOKE DETECTOR

WITH INTERCONNECT

AND TIMER

www.allegromicro.com

I/O OPERATION

INTERNAL

CLOCK

HORN

V2 IN

I/O

1.67 s

40 ms

72 CLOCK CYCLES

V2 OUT

I/O

INTERNAL

CLOCK

LOCAL ALARM MODE

NO LOW BATTERY

REMOTE ALARM MODE

NO LOW BATTERY

Dwg. WC-004-1

HORN

12 CLOCK

CYCLES

NO I/O CHARGE DUMP

12 CLOCK

CYCLES

HORN CYCLE NOT SELF COMPLETING

AFTER REMOTE OR LOCAL ALARM CONDITION IS REMOVED

SINGLE HORN PULSE IN PROGRESS IS SELF COMPLETING

AFTER LOCAL ALARM CONDITION IS REMOVED

SHADED AND UNSHADED AREAS

ARE DIFFERENT TIME SCALES

I/O CHARGE DUMP

5367

SMOKE DETECTOR

WITH INTERCONNECT

AND TIMER

115 Northeast Cutoff, Box 15036

Worcester, Massachusetts 01615-0036 (508) 853-5000

Dimensions in Inches

(controlling dimensions)

Dimensions in Millimeters

(for reference only)

NOTES:1. Lead thickness is measured at seating plane or below.

2. Lead spacing tolerance is non-cumulative.

3. Exact body and lead configuration at vendor’s option within limits shown.

4. Supplied in standard sticks/tubes of 25 devices.

0.014

0.008

0.300

BSC

Dwg. MA-001-16A in

0.430

MAX

0.280

0.240

0.210

MAX

0.070

0.045

0.015

MIN

0.022

0.014

0.100

BSC

0.005

MIN

0.150

0.115

0.775

0.735

0.355

0.204

7.62

BSC

Dwg. MA-001-16A mm

10.92

MAX

7.11

6.10

5.33

MAX

1.77

1.15

0.39

MIN

0.558

0.356

2.54

BSC 0.13

MIN

3.81

2.93

19.68

18.67

5367

SMOKE DETECTOR

WITH INTERCONNECT

AND TIMER

www.allegromicro.com

The products described here are manufactured under one or more

U.S. patents or U.S. patents pending.

Allegro MicroSystems, Inc. reserves the right to make, from time to

time, such departures from the detail specifications as may be required

to permit improvements in the performance, reliability, or

manufacturability of its products. Before placing an order, the user is

cautioned to verify that the information being relied upon is current.

Allegro products are not authorized for use as critical components

in life-support devices or systems without express written approval.

The information included herein is believed to be accurate and

reliable. However, Allegro MicroSystems, Inc. assumes no responsi-

bility for its use; nor for any infringement of patents or other rights of

third parties which may result from its use.

5367

SMOKE DETECTOR

WITH INTERCONNECT

AND TIMER

115 Northeast Cutoff, Box 15036

Worcester, Massachusetts 01615-0036 (508) 853-5000

SAFETY & SECURITY ICs

Part

Number Function

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A5364CA Ionization-type smoke detector with interconnect, reverse-battery protection,

and temporal horn pattern

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and temporal horn pattern

A5368CA Ionization-type smoke detector with interconnect, timer, reverse-battery protection,

and temporal horn pattern