PHOTOELECTRIC SMOKE DETECTOR
WITH INTERCONNECT AND TIMER
The A5358CA is a low-current BiCMOS circuit providing all of the
required features for a photoelectric type smoke detector. This device
can be used in conjunction with an infrared photoelectric chamber to
sense scattered light from smoke particles. Special features are
incorporated in the design to facilitate calibration and testing of the
finished detector. The device is designed to comply with Underwriters
Laboratories Specification UL217 and British Standard BS 5446,
Part 1.
A variable-gain photo amplifier can be directly interfaced to an
infrared emitter/detector pair. The amplifier gain levels are determined
by two external capacitors that are then internally selected depending
on the operating mode. Low gain is selected during standby and timer
modes. During a local alarm this low gain is increased (internally) by
~10% to reduce false triggering. High gain is used during the push-
button test and during standby to periodically monitor the chamber
sensitivity.
The internal oscillator and timing circuitry keeps standby power to
a minimum by sensing for smoke every 10 seconds in a 10
s window.
A special three-stage speedup sensing scheme is incorporated to
minimize the time to an audible alarm and also to reduce false trigger-
ing. Also, two consecutive cycles of degraded chamber sensitivity are
required for a warning signal to occur.
The A5358CA is supplied in a low-cost 16-pin dual in-line plastic
package. It is rated for continuous operation over the temperature
range of -25
C to +75
C.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
OSC. &
TIMING
HORN
DRIVER
TEST
DETECT
HUSH
OSC. CAP.
HORN
HORN
SUPPLY
V
SS
C
I / O
C
STROBE
+ SUPPLY
V
DD
TIMING RES.
FEEDBACK
1
2
LED
IRED
LOGIC
1
2
Data Sheet
26110.10A
Dwg. PC-007
ABSOLUTE MAXIMUM RATINGS
(Voltages are referenced to V
SS
)
Supply Voltage Range,
V
DD
.................................... -0.5 V to +15 V
Input Voltage Range,
V
IN
............................ -0.3 V to V
DD
+ 0.3 V
Input Current, I
IN
................................... 10 mA
Operating Temperature Range,
T
A
..................................... -25
C to +75
C
Storage Temperature Range,
T
S
................................... -55
C to +125
C
CAUTION: CMOS devices have input static
protection but are susceptible to damage if exposed
to extremely high static electrical charges.
Always order by complete part number: A5358CA .
FEATURES
s
Interconnect Up to 50 Detectors
s
Piezoelectric Horn Driver
s
All Internal Low-Battery Detection
s
Power-ON Reset
s
Internal Timer & Control for Reduced Sensitivity
s
Built-In Circuits to Reduce False Triggering
s
6 V to 12 V Operating Voltage Range
s
ESD-Protection Circuitry on All Pins
5358
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.
5358
PHOTOELECTRIC SMOKE DETECTOR
with INTERCONNECT and TIMER
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
2
FUNCTIONAL BLOCK DIAGRAM
4
STROBE
SUPPLY
14
VSS
9 V
+ SUPPLY
I / O
TIMING RES.
FEEDBACK
DETECT
OSC. CAP.
POWER-ON
RESET
OSCILLATOR
& TIMING
LOGIC
+
+
HORN 1
HORN
2
LED
TEST
+V
+V
V
DD
16
7
11
10
9
8
13
12
5
3
V
DD
Dwg. FC-006
1
2
LOW BATTERY
C1
C2
HUSH
15
6
IRED
PHOTO AMP
V DD
BAND-GAP
REFERENCE
Copyright 1995, 2002 Allegro MicroSystems, Inc.
5358
PHOTOELECTRIC SMOKE DETECTOR
with INTERCONNECT and TIMER
3
www.allegromicro.com
Test
Limits
Characteristic
Symbol
Test Conditions
Pin
V
DD
Min.
Typ.
Max.
Units
Supply Voltage Range
V
DD
5
6.0
12
V
Operating Supply Current
I
DD
Average Standby
5
12
12
A
Configured per Figure 1
During Strobe ON, I
RED
OFF,
5
12
2.0
mA
Configured per Figure 1
During Strobe ON, I
RED
ON,
5
12
3.0
mA
Configured per Figure 1
Low-Level Input Voltage
V
IL
7
9
1.5
V
10
9
2.7
V
16
9
7.0
V
15
9
0.5
V
High-Level Input Voltage
V
IH
7
9
3.2
V
10
9
6.3
V
16
9
8.5
V
15
9
1.6
V
Input Leakage High
I
IH
V
IN
= V
DD
, Strobe Active,
1, 2
12
100
nA
Pin 12 @ V
DD
V
IN
= V
DD
3, 10, 12
12
100
nA
Input Leakage Low
I
IL
V
IN
= V
ST
, Strobe Active,
1, 2, 3
12
-100
nA
Pin 12 @ V
DD
V
IN
= V
SS
10, 12
12
-100
nA
15, 16
12
-1.0
A
Input Pull-Down Current
I
IN
V
IN
= V
DD
16, 15
9
0.25
10
A
No Local Smoke, V
IN
= V
DD
7
9
20
80
A
No Local Smoke, V
IN
= 17 V
7
12
140
A
Low-Level Output Voltage
V
OL
I
O
= 10 mA
11
6.5
0.6
V
I
O
= 16 mA
8, 9
6.5
1.0
V
I
O
= 5 mA
13
6.5
0.5
V
High-Level Output Voltage
V
OH
I
O
= -16 mA
8, 9
6.5
5.5
V
Strobe Output Voltage
V
ST
Inactive I
O
= -1
A
4
12
V
DD
- 0.1
V
Active, I
O
= 100
A to 500
A
4
9
V
DD
- 5.25
V
DD
- 4.75
V
Continued...
DC ELECTRICAL CHARACTERISTICS at T
A
= -25
C to +75
C*, V
SS
= 0 V, in typical application
(unless otherwise noted).
5358
PHOTOELECTRIC SMOKE DETECTOR
with INTERCONNECT and TIMER
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
4
Test
Limits
Characteristic
Symbol
Test Conditions
Pin
V
DD
Min.
Typ.
Max.
Units
Line Regulation
V
ST(
VDD)
Active, V
DD
= 6 V to 12 V
4
-60
dB
Strobe Temperature Coeff.
ST
V
DD
= 6 V to 12 V
4
0.01
%/
C
I
RED
Output Voltage
V
IRED
Inactive I
O
= 1
A, T
A
= +25
C
6
12
0.1
V
Active I
O
= -6 mA, T
A
= +25
C
6
9
2.85
3.1
3.35
V
Line Regulation
V
IRED(
VDD)
Active, V
DD
= 6 V to 12 V
6
-35
dB
I
RED
Temperature Coefficient
IRED
V
DD
= 6 V to 12 V
6
+0.40
%/
C
High-Level Output Current
I
OH
V
DD
= Alarm, I/O active,
7
9
-4.0
mA
V
O
= V
DD
- 2 V
OFF Leakage Current High
I
OZ
V
O
= V
DD
11, 13
12
1.0
A
OFF Leakage Current Low
I
OZ
V
O
= V
SS
11, 13
12
-1.0
A
Low V
DD
Alarm Threshold
V
DD(th)
5
-
6.9
7.2
7.5
V
Common Mode Voltage
V
IC
Any Alarm Condition
1, 2, 3
-
V
DD
- 4
V
DD
- 2
V
Smoke Comparator Ref. Volt.
V
REF
Any Alarm Condition
Internal
-
V
DD
- 3.7
V
DD
- 3.3
V
DC ELECTRICAL CHARACTERISTICS, continued
AC ELECTRICAL CHARACTERISTICS at T
A
= -25
C to +75
C*, V
SS
= 0 V, in typical application
(unless otherwise noted).
Test
Limits
Characteristic
Symbol
Test Conditions
Pin
V
DD
Min.
Typ.
Max.
Units
Oscillator Period
t
osc
12
9
9.4
10.5
11.5
ms
Led Pulse Period
t
led1
No Local or Remote Smoke
11
9
39
48
s
t
led4
Remote Smoke Only
11
9
None
t
led6
Local Smoke or Test
11
9
0.60
0.67
0.74
s
t
led7
Timer Mode, No Alarm
11
9
9.67
10.8
11.8
s
Led Pulse Width
t
w(led)
11
9
9.5
11.5
ms
Continued...
* Limits over the operating temperature range are based on characterization data.
Characteristics are production tested at +25
C only.
Typical values are at +25
C and are given for circuit design information only.
5358
PHOTOELECTRIC SMOKE DETECTOR
with INTERCONNECT and TIMER
5
www.allegromicro.com
Test
Limits
Characteristic
Symbol
Test Conditions
Pin
V
DD
Min.
Typ.
Max.
Units
Strobe Pulse Period
t
st1
No Local or Remote Smoke
4
9
9.6
11.9
s
t
st2
After 1 of 3 Valid Samples
4
9
2.42
2.70
2.96
s
t
st3
After 2 of 3 Valid Samples
4
9
1.21
1.34
1.47
s
and During Local Alarm
t
st4
Remote Alarm
4
9
9.67
10.8
11.8
s
t
st5
Chamber Test or Low Supply
4
9
38.9
47.1
s
Test, No Local Alarm
t
st6
Pushbutton Test, No Alarm
4
9
300
336
370
ms
Strobe Pulse Width
t
w(st)
4
9
9.5
11.5
ms
I
RED
Pulse Period
t
ired1
No Local or Remote Smoke
6
9
9.6
11.9
s
t
ired2
After 1 of 3 Valid Samples
6
9
2.42
2.70
2.96
s
t
ired3
After 2 of 3 Valid Samples
6
9
1.21
1.34
1.47
s
and During Local Alarm
t
ired4
Remote Alarm
6
9
9.67
10.8
11.8
s
t
ired5
Chamber Test, No Local Alarm
6
9
38.9
47.1
s
t
ired6
Pushbutton Test, No Alarm
6
9
300
336
370
ms
I
RED
Pulse Width
t
w(ired)
6
9
94
116
s
I
RED
Rise Time
t
r(ired)
10% to 90%
6
30
s
I
RED
Fall Time
t
f(ired)
90% to 10%
6
200
s
I/O to Active Delay
t
d(io)
Local Alarm
7
9
0
s
Rising Edge on I/O to Alarm
t
r(io)
No Local Alarm
7
9
1.34
s
Horn Warning Pulse Period
t
horn
Low Supply and Degraded
8, 9
9
38.9
47.1
s
Chamber Sensitivity
Horn Warning Pulse Width
t
w(horn)
Low Supply and Degraded
8, 9
9
9.5
11.5
ms
Chamber Sensitivity
Horn ON Time
t
on(horn)
Local or Remote Alarm
8, 9
9
252
ms
Horn OFF Time
t
off(horn)
Local or Remote Alarm
8, 9
9
84
ms
AC ELECTRICAL CHARACTERISTICS, continued.
* Limits over the operating temperature range are based on characterization data.
Characteristics are production tested at +25
C only.
Typical values are at +25
C and are given for circuit design information only.
5358
PHOTOELECTRIC SMOKE DETECTOR
with INTERCONNECT and TIMER
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
6
PIN AND CIRCUIT DESCRIPTION
(In Typical Application)
PIN 1 (C
1
)
A capacitor connected to this pin determines the gain
of the photo amplifier during the push-to-test mode and
during the chamber monitor test. A typical value for this
high-gain mode is 0.047
F but should be selected
based on the photo chamber background reflections
reaching the detector and the desired level of sensitivity.
A
e
1+(C
1
/10) where C
1
is in pF. A
e
should not
exceed 10 000.
PIN 2 (C
2
)
A capacitor connected to this pin determines the gain
of the photo amplifier during standby. A typical value for
this low-gain mode is 4700 pF but should be selected
based on a specific photo chamber and the desired level
of sensitivity to smoke. A
e
1+(C
2
/10) where C
2
is in pF.
A
e
should not exceed 10 000. This gain increases by a
nominal 10% after a local alarm is detected (three con-
secutive detections). Coupling of other signals to C
2
(C
1
and the DETECT inputs also) must be minimized.
A resistor must be installed in series with C
2
.
PIN 3 (DETECT)
This is the input to the photo amplifier and is con-
nected to the cathode of the photo diode. The photo
diode is operated at zero bias and should have low dark-
leakage current and low capacitance.
PIN 4 (STROBE)
This output provides a strobed, regulated voltage of
V
DD
5 V. The minus side of all internal and external
photo amplifier circuitry is referenced to this pin.
PIN 5 (V
DD
)
This pin is connected to the most-positive supply
potential and can range from 6 V to 12 V with respect
to V
SS
.
PIN 6 (I
RED
)
This output provides a pulsed base current for the
external npn transistor, which drives the IR emitter. Its
beta should be greater than 100. The I
RED
output is not
active, to minimize noise impact, when the horn and
visible LED outputs are active.
PIN 7 (I/O)
A connection at this pin allows multiple smoke detec-
tors to be interconnected. If a local smoke condition
occurs, this pin is driven high. As an input, this pin is
sampled nominally every 1.35 seconds during standby.
Any local-alarm condition causes this pin to be ignored as
an input.
This pin has an on-chip pull-down resistor and must
be left unconnected if not used. In application, there is a
series current-limiting resistor to other smoke alarms.
PIN 8 (HORN
1
)
PIN 9 (HORN
2
)
PIN 10 (FEEDBACK)
These three pins are used in conjunction with external
passive components and a self-resonating piezoelectric
transducer. HORN
1
is connected to the piezo metal
support electrode; the complementary output, HORN
2
, is
connected to the ceramic electrode and the FEEDBACK
input to the feedback electrode.
A continuous modulated tone indicates either a local
or remote alarm condition. A short (10 ms) chirp indicates
a low-battery condition or degraded chamber sensitivity.
The low-battery chirp occurs almost simultaneous with the
visible LED flash. If the FEEDBACK pin is not used, it
must be connected to V
DD
or V
SS
.
Continued...
5358
PHOTOELECTRIC SMOKE DETECTOR
with INTERCONNECT and TIMER
7
www.allegromicro.com
PIN AND CIRCUIT DESCRIPTION, continued
PIN 11 (LED)
This open-drain NMOS output is used to directly drive
a visible LED. The load for the low-battery test is applied
to this output. The low-battery test does not occur coinci-
dent with any other test or alarm signal. The LED also
indicates detector status as follows (with component
values as in the typical application, all times nominal):
Standby
- Pulses every 43 seconds.
Local Smoke
- Pulses every 0.67 second.
Remote Alarm - No pulses.
Test Mode
- Pulses every 0.67 second.
Timer Mode
- Pulses every 10 seconds.
PIN 12 (OSC. CAP.)
A capacitor between this pin and V
DD
, along with a
parallel resistor, forms part of a two-terminal oscillator and
sets the internal clock low time. With component values
as shown, this nominal time is 11 ms and essentially the
oscillator period.
PIN 13 (TIMING RES.)
A resistor between this pin and OSC. CAP. (pin 12) is
part of the two-terminal oscillator and sets the internal
clock high time, which is also the I
RED
pulse width. With
component values as shown, this nominal time is 105
s.
PIN 14 (V
SS
)
This pin is connected to the most negative supply
potential (usually ground).
PIN 15 (HUSH)
This input pin serves two purposes in normal opera-
tion. It serves as an enable for the internal 10-minute
(nominal) timer and also as the reference for the smoke
comparator during the timer mode. This reference is
established by a resistive divider between V
DD
and
STROBE (R
X1
and R
X2
). This allows the detector to have
a different sensitivity set point during the timer mode. If
the timer mode is not used, this pin can be left open or
connected to V
SS
, which disables this mode.
PIN 16 (TEST)
This pin has an internal pull-down device and is used
to manually invoke two test modes and a Timer Mode.
The Push-to-Test Mode is initiated by a high logic
level on this pin (usually the depression of a normally
open push-button switch to V
DD
). After one oscillator
cycle, I
RED
pulses every 336 ms (nominal) and amplifier
gain is increased by internal selection of C
1
. Background
reflections in the smoke chamber can be used to simulate
a smoke condition. After the third I
RED
pulse, a successful
test (three consecutive simulated smoke conditions)
activates the horn drivers and the I/O pin. When the
push-button is released, the input returns to V
SS
due to
the internal pull down. After one oscillator cycle, the
amplifier gain returns to normal and after three additional
I
RED
pulses (less than one second), the device exits this
mode and returns to standby. This high-to-low transition
on pin 16 also resets and starts the 10 minute hush timer
(timer mode).
Pin Name
Pin No. Configuration
I/O
7
Disabled as an output. A logic
high on this pin places the photo
amplifier output on pin 1 or pin 2
as determined by pin 15. The
amplifier output appears as
pulses.
HUSH
15
If the I/O pin is high, this pin
controls the amplifier gain capaci
tor. If pin 15 is low, normal gain is
selected and the amplifier output
is on pin 1. If pin 15 is high,
supervisory gain is selected and
the amplifier output is on pin 2.
FEEDBACK 10
If pin 7 is high and pin 15 is low
(normal gain), taking this pin to a
high logic level increases the
amplifier gain by ~10% (hyster-
esis).
OSC. CAP. 12
This pin may be driven by an
external clock source. Driving
this pin low and high drives the
internal clock low and high. The
external RC network may remain
intact.
5358
PHOTOELECTRIC SMOKE DETECTOR
with INTERCONNECT and TIMER
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
8
TYPICAL APPLICATION
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
OSC. &
TIMING
HORN
DRIVER
V
SS
V
DD
LOGIC
Dwg. EC-006
TO/FROM
OTHER
UNITS
9 V
PUSH
TO
TEST
V
DD
CONNECT FOR TIMER MODE OR "HUSH" OPERATION
CONNECT FOR
NON-TIMER MODE
OPERATION
SMOKE
CHAMBER
R
X1
R
X2
8.2k
5k
4.7k
1k
100
F
22
100k
1500pF
10M
1000pF
220k
100k
560
200k
220
330
+
22
F
+
C
1
C
2
The Diagnostic Test Mode is initiated by pulling this
pin below V
SS
and continuously sourcing 400
A from the
pin for at least one clock cycle on the OSC. CAP. pin.
This mode is used to facilitate calibration and test of the
IC and the assembled detector. In this mode, certain
device pins are reconfigured as described below. In this
mode, the I
RED
pulse rate is increased to one every OSC.
CAP. cycle and the STROBE pin is always active. To exit
this mode, the test pin is floated for at least one OSC.
CAP. cycle.
Pin Name
Pin No. Configuration
HORN
1
8
This pin is reconfigured as the
smoke integrator output. Three
consecutive smoke detections
will cause this pin to go high
and three consecutive no-
smoke detections cause this
pin to go low.
LED
11
This pin becomes a low-battery
indicator. The open-drain
NMOS output is normally OFF.
If V
DD
falls below the low-
battery threshold, the output
turns ON.
PIN AND CIRCUIT DESCRIPTION, continued
5358
PHOTOELECTRIC SMOKE DETECTOR
with INTERCONNECT and TIMER
9
www.allegromicro.com
STANDBY TIMING DIAGRAM
(not to scale)
Dwg. WC-008
OSC. CAP
(PIN 12)
INTERNAL
CLOCK
IRED
(PIN 6)
STROBE
(PIN 4)
LED
(PIN 11)
SAMPLE
SMOKE
HORN
ENABLE
NO LOW SUPPLY
CHAMBER SENSITIVITY NORMAL
LOW SUPPLY OR
DEGRADED SENSITIVITY
WARNING CHIRPS ARE OFFSET
WARNING
CHIRP
t osc
t w(st)
t st
t w(led)
t led
t horn
t w(horn)
t w(ired)
t ired
5358
PHOTOELECTRIC SMOKE DETECTOR
with INTERCONNECT and TIMER
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
10
LOCAL ALARM TIMING DIAGRAM
(not to scale)
Dwg. WC-009
IRED
(PIN 6)
STROBE
(PIN 4)
LED
(PIN 11)
I/O
(PIN 7)
HORN
ENABLE
TEST
REMOTE SMOKE
(NO LOCAL SMOKE)
LOCAL SMOKE
(REMOTE SMOKE =
DON'T CARE)
(AS OUTPUT)
(AS INPUT)
(AS OUTPUT)
(NO PULSES)
NO SMOKE
3RD STROBE WITHOUT SMOKE
3RD STROBE WITH SMOKE
10%
90%
w(ired)
w(st)
t
led1
r(io)
ired6
w(led)
on(horn)
off(horn)
led6
st6
t
ired3
st3
ired4
st4
on(horn)
off(horn)
t
t
t
t
t
t
t
t
t
t
t
t
t
t
10%
f(ired)
t
5358
PHOTOELECTRIC SMOKE DETECTOR
with INTERCONNECT and TIMER
11
www.allegromicro.com
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
16
1
8
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
9
0.775
0.735
0.355
0.204
7.62
BSC
Dwg. MA-001-16A mm
10.92
MAX
16
1
8
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
9
19.68
18.67
5358
PHOTOELECTRIC SMOKE DETECTOR
with INTERCONNECT and TIMER
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
12
SAFETY & SECURITY ICs
Part
Number
Function
A5347CA
Ionization-type smoke detector with interconnect and timer
A5348CA
Ionization-type smoke detector with interconnect, timer, and reverse-battery protection
A5349CA
Ionization-type smoke detector with interconnect and timer for ac line operation
A5350CA
Ionization-type smoke detector with interconnect and reverse-battery protection
A5354CA
Ionization-type smoke detector with interconnect and reverse-battery protection
A5355CA
Ionization-type smoke detector with interconnect
A5358CA
Photoelectric-type smoke detector with interconnect and timer
A5364CA
Ionization-type smoke detector with interconnect, reverse-battery protection,
and temporal horn pattern
A5366CA
Photoelectric-type smoke detector with interconnect, timer, and temporal horn pattern
A5367CA
Ionization-type smoke detector with interconnect, timer, reverse-battery protection,
and temporal horn pattern
A5368CA
Ionization-type smoke detector with interconnect, timer, reverse-battery protection,
and temporal horn pattern
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.
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