A5355: Ionization-Type Smoke Detector with Interconnect

Data Sheet
26110.5A
5355
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 A5355CA 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 A5355CA 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.
Dwg. PC-004-1
D
E
U
N
P
e
c
n
FEATURES
I
T
ABSOLUTE MAXIMUM RATINGS
N
O
(Voltages are referenced to VSS)
Supply Voltage Range,
VDD ................................ -0.5 V to +15 V
C
S
Reverse Battery (10.5 V) ....................... 20 s
I
D
—
Input Voltage Range,
VIN ........................ -0.3 V to VDD + 0.3 V
■
■
■
■
■
■
y
l
n
o
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
r
o
F
f
e
r
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: A5355CA .
5355
SMOKE DETECTOR
with INTERCONNECT
FUNCTIONAL BLOCK DIAGRAM AND TYPICAL APPLICATION
+ SUPPLY V
I/O
DD
6
9V
2
+
V
FEEDBACK
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
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
Copyright © 1996, 2003 Allegro MicroSystems, Inc.
Dwg. FC-001-3
5355
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
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
TA = 0 to 50°C
7.2
—
7.8
V
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
Input Offset Voltage
Common Mode Range
Active Guard Impedance
Oscillator Period
Alarm
Oscillator Pulse Width
4
Low Voltage Threshold
6
Horn Output Voltage
Horn Output ON Time
Horn Output OFF Time
10-11
10-11
10-11
LED Output ON Current
5
LED Output ON Time
5
LED Output OFF Time
5
No Alarm, In Standby
32
40
48
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
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.
5355
SMOKE DETECTOR
with INTERCONNECT
CIRCUIT DESCRIPTION
The A5355CA 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, polystyrene, or polypropylene).
Detector Circuitry. 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 must be
externally adjusted to the individual characteristics of the
ionization chamber by connecting resistors between pin
13 and VDD, and 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.
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
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.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
5355
SMOKE DETECTOR
with INTERCONNECT
TYPICAL APPLICATION
1
PUSH
TO
TEST
16
NC
200 Ω
3
NC
330 Ω
13
OSC. &
TIMING
NOTE 1
5
6
12
V DD
8.2 MΩ
11
HORN
DRIVER
7
1 µF
0.1 µF
4.7 MΩ
4
14
10
8
V SS
9
330 kΩ
NOTE
2
15
LOGIC
200 kΩ
2
1 MΩ
TO
OTHER
UNITS
4.7 MΩ
200 kΩ
9V
0.001 µF
Dwg. EC-005-5
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
SMOKE
CHAMBER
LOW BATTERY
WARNING
HORN
ON
HORN
OFF
V15 > V13 (SMOKE)
V15 < V13 (NO SMOKE)
Dwg. WC-003-1
5355
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
5355
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
5355
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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