A5368: Ionization-Type Smoke Detector with Interconnect, Timer, Reverse-Battery Protection

Data Sheet
26110.8†
5368
SMOKE DETECTOR
WITH INTERCONNECT AND TIMER
TIMER START
1
I/O
2
LOW-V SET
3
TIMER OUT
4
LED
5
+ SUPPLY
6
TIMING RES.
7
FEEDBACK
8
LOGIC
16
GUARD 2
15
DETECT. IN
14
GUARD 1
13
SENSITIVITY
SET
12
OSC. CAP.
11
HORN 2
10
HORN 1
9
– SUPPLY
The A5368CA 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.
T
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—
OSC. &
TIMING
V DD
HORN
DRIVER
V SS
Dwg. PC-004
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.
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
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 A5368CA 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
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.
Always order by complete part number: A5368CA .
5368
SMOKE DETECTOR
WITH INTERCONNECT
AND TIMER
FUNCTIONAL BLOCK DIAGRAM AND TYPICAL APPLICATION
+ SUPPLY V
I/O
DD
6
9V
2
+
V
FEEDBACK
DD
8
11
HORN
–
+
3
2
10
HORN 1
LOW-V
SET
LOGIC
+V
5
LED
13
POWER-ON
RESET
–
+
SENSITIVITY
SET
TIMING RES.
7
OSCILLATOR
& TIMING
12
–
+
– SUPPLY
4
9
TIMER OUT
V SS
14
DETECT. 15
IN
16
GUARD 1
GUARD 2
+V
OSC. CAP.
1
TIMER
START
+V
Dwg. FC-001B
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 1998, 2002 Allegro MicroSystems, Inc.
5368
SMOKE DETECTOR
WITH INTERCONNECT
AND TIMER
ELECTRICAL CHARACTERISTICS at TA = +25°C, VDD = 9.0 V, VSS = 0 V, C12 = 0.1 µF,
R7 = 8.2 MΩ (unless otherwise noted).
Limits
Test
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
14-15
Active Guard
—
—
±100
mV
16-15
Active Guard
—
—
±100
mV
15-13
Detect Comparator
—
—
±50
mV
13
No Alarm to Alarm
90
130
170
mV
14-15
Guard Amplifier
2.0
—
VDD - 0.5
V
13-15
Smoke Comparator
0.5
—
VDD - 2.0
V
14
to VSS
—
10
—
kΩ
16
to VSS
—
500
—
kΩ
12
No Alarm
1.34
1.67
2.00
s
32
40
48
ms
8.0
10
12
ms
Input Offset Voltage
Hysteresis
Common Mode Range
Active Guard Impedance
Oscillator Period
Alarm
Oscillator Pulse Width
4
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
%
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
Alarm (see figure, time “A”)
450
500
550
ms
Low Battery
8.0
10
12
ms
Alarm (see figure, time “B”)
450
500
550
ms
Alarm (see figure, time “C”)
1350
1500
1650
ms
Low Battery
32
40
48
s
VIH
4.5
—
—
V
VIL
—
—
2.5
V
Horn Output Voltage
Horn Output ON Time
Horn Output OFF Time
Timer Start Logic Levels
NOTE 1:
NOTE 2:
10-11
10-11
10-11
1
Continued next page . . .
Negative current is defined as coming out of (sourcing) the specified device pin.
Alarm (Smoke) Condition is defined as V15 < V13; No Alarm (No Smoke) Condition as V15 > V13.
www.allegromicro.com
5368
SMOKE DETECTOR
WITH INTERCONNECT
AND TIMER
ELECTRICAL CHARACTERISTICS continued
Limits
Test
Characteristic
Pin
Test Conditions
Min.
Typ.
Max.
Units
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
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 Current
2
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
NOTE 1:
NOTE 2:
Negative current is defined as coming out of (sourcing) the specified device pin.
Alarm (Smoke) Condition is defined as V15 < V13; No Alarm (No Smoke) Condition as V15 > V13.
CIRCUIT DESCRIPTION
The A5368CA 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 nosmoke 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, polystyrene, 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 external 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.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
5368
SMOKE DETECTOR
WITH INTERCONNECT
AND TIMER
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
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TO
OTHER
UNITS
200 kΩ
TIMER
MODE
200 kΩ
PUSH
TO
TEST
16
1
200 Ω
2
NOTE
3
15
LOGIC
3
14
4
5
6
8.2 MΩ
12
V DD
0.1 µF
11
HORN
DRIVER
7
1 µF
NOTE
1
13
OSC. &
TIMING
330 Ω
10
8
V SS
9
200 kΩ
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, however, 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.
9V
1 MΩ
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 decreased 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.
TYPICAL APPLICATION
50 kΩ
Sensitivity Adjust. The detector sensitivity 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.
0.001 µF
NOTE 2
Dwg. EC-005A
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.
unit. An internal NMOS device acts as a charge dump to aid in applications 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.
5368
SMOKE DETECTOR
WITH INTERCONNECT
AND TIMER
TIMING DIAGRAMS IN TYPICAL APPLICATION
NON-TIMER MODE
NO ALARM
NO LOW BATTERY
STANDBY MODE
ALARM
NO LOW BATTERY
ALARM AND
LOW BATTERY
NO ALARM
LOW BATTERY
V12
OSC. CAP
10 ms
1.67 s
40 ms
24 CLOCK CYCLES
INTERNAL
CLOCK
24 CLOCK CYCLES
LED
30 CLOCK CYCLES
19 CLOCK CYCLES
LED OFF
24 CLOCK CYCLES
LED
ON
13 CLOCK
CYCLES
SMOKE
COMPARATOR
SAMPLE
HORN
12 CLOCK
CYCLES
12 CLOCK
CYCLES
HORN
ON TIME
"A"
HORN
OFF TIME
"B"
36 CLOCK CYCLES
LOW BATTERY
WARNING
HORN OFF TIME
"C"
V15 < V13 (SMOKE)
SMOKE
CHAMBER
V15 > V13 (NO SMOKE)
SHADED AND UNSHADED AREAS
ARE DIFFERENT TIME SCALES
I/O CHARGE DUMP
73 CLOCK CYCLES
I/O
Dwg. WC-003-2
TIMER MODE
V12
OSC. CAP
10 ms
1.67 s
INTERNAL
CLOCK
368 CLOCK CYCLES
TIMER
START
TIMER
OUT
6 CLOCK CYCLES
OUTPUTS OFF (HIGH Z)
LED
END OF TIMER
NOTIFICATION
LED
ON
HORN
I/O CHARGE DUMP
I/O
Dwg. WC-005-1
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
5368
SMOKE DETECTOR
WITH INTERCONNECT
AND TIMER
I/O OPERATION
REMOTE ALARM MODE
NO LOW BATTERY
1.67 s
40 ms
INTERNAL
CLOCK
12 CLOCK
CYCLES
HORN
NO I/O CHARGE DUMP
V2 IN
I/O
HORN CYCLE NOT SELF COMPLETING
AFTER REMOTE OR LOCAL ALARM CONDITION IS REMOVED
SHADED AND UNSHADED AREAS
ARE DIFFERENT TIME SCALES
SINGLE HORN PULSE IN PROGRESS IS SELF COMPLETING
AFTER LOCAL ALARM CONDITION IS REMOVED
LOCAL ALARM MODE
NO LOW BATTERY
INTERNAL
CLOCK
12 CLOCK
CYCLES
HORN
72 CLOCK CYCLES
I/O CHARGE DUMP
V2 OUT
I/O
Dwg. WC-004-1
www.allegromicro.com
5368
SMOKE DETECTOR
WITH INTERCONNECT
AND TIMER
Dimensions in Inches
(controlling dimensions)
0.014
0.008
9
16
0.430
MAX
0.280
0.240
0.300
BSC
1
0.070
0.045
0.100
0.775
0.735
8
0.005
BSC
MIN
0.210
MAX
0.015
0.150
0.115
MIN
0.022
0.014
Dwg. MA-001-16A in
Dimensions in Millimeters
(for reference only)
0.355
0.204
9
16
10.92
MAX
7.11
6.10
7.62
BSC
1
1.77
1.15
2.54
19.68
18.67
BSC
8
0.13
MIN
5.33
MAX
0.39
3.81
2.93
MIN
0.558
0.356
NOTES:1.
2.
3.
4.
Dwg. MA-001-16A mm
Lead thickness is measured at seating plane or below.
Lead spacing tolerance is non-cumulative.
Exact body and lead configuration at vendor’s option within limits shown.
Supplied in standard sticks/tubes of 25 devices.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
5368
SMOKE DETECTOR
WITH INTERCONNECT
AND TIMER
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 responsibility for its use; nor for any infringement of patents or other rights of
third parties which may result from its use.
www.allegromicro.com
5368
SMOKE DETECTOR
WITH INTERCONNECT
AND TIMER
SAFETY & SECURITY ICs
Part
Number
A5347CA
A5348CA
A5349CA
A5350CA
A5354CA
A5355CA
A5358CA
A5364CA
A5366CA
A5367CA
A5368CA
Function
Ionization-type smoke detector with interconnect and timer
Ionization-type smoke detector with interconnect, timer, and reverse-battery protection
Ionization-type smoke detector with interconnect and timer for ac line operation
Ionization-type smoke detector with interconnect and reverse-battery protection
Ionization-type smoke detector with interconnect and reverse-battery protection
Ionization-type smoke detector with interconnect
Photoelectric-type smoke detector with interconnect and timer
Ionization-type smoke detector with interconnect, reverse-battery protection,
and temporal horn pattern
Photoelectric-type smoke detector with interconnect, timer, and temporal horn pattern
Ionization-type smoke detector with interconnect, timer, reverse-battery protection,
and temporal horn pattern
Ionization-type smoke detector with interconnect, timer, reverse-battery protection,
and temporal horn pattern
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
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