A5354: Smoke Detector with Interconnect

Data Sheet
26110.6
5354
SMOKE DETECTOR
WITH INTERCONNECT
NO CONNECT.
1
I/O
2
LOW-V SET
3
NO CONNECT.
4
LED
5
+ SUPPLY
6
TIMING RES.
7
FEEDBACK
8
NC
LOGIC
NC
V DD
OSC. &
TIMING
HORN
DRIVER
V SS
16
GUARD 2
15
DETECT. IN
14
GUARD 1
13
SENSITIVITY
SET
12
OSC. CAP.
11
HORN 2
10
HORN 1
9
– SUPPLY
The A5354CA 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
C
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.
U
D
O
R
The A5354CA 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. Similar devices, with an internal timer to allow
for a period of reduced sensitivity (“hush”), are available as the
A5348CA.
N
O
Supply Voltage Range,
VDD ................................ -0.5 V to +15 V
C
S
Reverse Battery (10.5 V) ....................... 20 s
I
D
U
N
I
T
ABSOLUTE MAXIMUM RATINGS
(Voltages are referenced to VSS)
D
E
—
Input Voltage Range,
VIN ........................ -0.3 V to VDD + 0.3 V
e
r
e
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
Built-In Hysteresis Reduces False Triggering
r
o
F
e
c
n
o
f
e
r
FEATURES
■
■
■
■
■
■
■
P
y
l
n
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: A5354CA .
5354
SMOKE DETECTOR
with INTERCONNECT
FUNCTIONAL BLOCK DIAGRAM AND TYPICAL APPLICATION
+ SUPPLY V
DD
6
9V
I/O
2
+
FEEDBACK
V DD
8
11
HORN 2
10
–
+
3
HORN 1
LOW-V
SET
LOGIC
+V
5
LED
13
POWER-ON
RESET
–
+
SENSITIVITY
SET
TIMING RES.
7
+V
OSC. CAP.
OSCILLATOR
& TIMING
12
–
+
– SUPPLY
9
V SS
14
DETECT. 15
IN
16
GUARD 1
GUARD 2
1
4
NO
CONNECTION
NO
CONNECTION
+V
Dwg. FC-001-4
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 1996, Allegro MicroSystems, Inc.
5354
SMOKE DETECTOR
with INTERCONNECT
ELECTRICAL CHARACTERISTICS at TA = +25°C, VDD = 9.0 V, VSS = 0 V, C12 = 0.1 µF,
R7 = 8.2 MΩ (unless otherwise noted).
Characteristic
Limits
Test
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
12
Low Voltage Threshold
6
TA = 0°C to 50°C
7.2
—
7.8
V
Sensitivity Adjust Voltage
13
V13/VDD, pin 13 open circuit
48.5
50
51.5
%
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
Alarm
120
160
208
ms
Low Battery
8.0
10
12
ms
Alarm
60
80
104
ms
Low Battery
32
40
48
s
VDD = 7.2 V, VOUT = 1.0 V
10
—
—
mA
8.0
10
12
ms
32
40
48
s
Horn Output Voltage
Horn Output ON Time
Horn Output OFF Time
10-11
10-11
LED Output ON Current
5
LED Output ON Time
5
LED Output OFF Time
5
No Alarm, In Standby
Continued next page . . .
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.
5354
SMOKE DETECTOR
with INTERCONNECT
ELECTRICAL CHARACTERISTICS continued
Characteristic
I/O Current
Limits
Test
Pin
Test Conditions
2
Min.
Typ.
Max.
Units
25
—
60
µA
Alarm, VI/O = VDD - 2.0 V
-7.5
—
—
mA
No Alarm, VI/O = VDD - 2.0 V
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: 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 A5354CA 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.
Because 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 160 ms
ON, 80 ms OFF. During the OFF time, smoke is again 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.
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.
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.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
5354
SMOKE DETECTOR
with INTERCONNECT
TYPICAL APPLICATION
1
200 kΩ
200 kΩ
9V
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.
16
NC
200 Ω
2
3
4
14
NC
330 Ω
5
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.
6
8.2 MΩ
12
V DD
0.1 µF
11
HORN
DRIVER
7
1 µF
NOTE
1
13
OSC. &
TIMING
10
8
9
V SS
330 kΩ
NOTE
2
PUSH
TO
TEST
15
LOGIC
1 MΩ
TO
OTHER
UNITS
0.001 µF
Dwg. EC-005-4
NOTE 1: An external resistor divider is used to adjust sensitivity for the
particular smoke chamber.
NOTE 2: A resistor to ground or VDD may be added to this pin to modify
low battery voltage threshold.
TIMING DIAGRAMS IN TYPICAL APPLICATION
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
INTERNAL
CLOCK
24 CLOCK CYCLES
LED
30 CLOCK CYCLES
24 CLOCK CYCLES
LED OFF
LED
ON
12 CLOCK CYCLES
6 CLOCK CYCLES
6 CLOCK CYCLES
SMOKE
COMPARATOR
SAMPLE
HORN
ON
HORN
SMOKE
CHAMBER
LOW BATTERY
WARNING
OFF
V15 < V13 (SMOKE)
V15 > V13 (NO SMOKE)
Dwg. WC-003
5354
SMOKE DETECTOR
with INTERCONNECT
I/O OPERATION
REMOTE ALARM MODE
1.67 s
40 ms
INTERNAL
CLOCK
4 CYCLES
HORN
2 CYCLES
HORN
ON
OFF
HORN NOT SELF COMPLETING
WHEN IN REMOTE ONLY ALARM
V2 IN
I/O
LOCAL ALARM MODE
INTERNAL
CLOCK
HORN
HORN
ON
OFF
72 CLOCK CYCLES
V2 OUT
I/O
Dwg. WC-004
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
5354
SMOKE DETECTOR
with INTERCONNECT
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. 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.
Dwg. MA-001-16A mm
5354
SMOKE DETECTOR
with INTERCONNECT
SAFETY & SECURITY ICs
SELECTION GUIDE
Part
Number
A3054KU/SU
A5347CA
A5348CA
A5349CA
A5354CA
A5355CA
A5358CA
Function
Multiplexed Two-Wire Hall-Effect Sensor
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
Photoelectric-Type Smoke Detector with Interconnect and Timer
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 design of its products.
The information included herein is believed to be accurate and reliable. However, Allegro
MicroSystems, Inc. assumes no responsibility for its use; nor for any infringements of patents or other
rights of third parties which may result from its use.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
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