A5350
Ionization Smoke Detector with Interconnect
Discontinued Product
These parts are no longer in production The device should not be
purchased for new design applications. Samples are no longer available.
Date of status change: November 2, 2009
Recommended Substitutions:
NOTE: For detailed information on purchasing options, contact your
local Allegro field applications engineer or sales representative.
Allegro MicroSystems, Inc. reserves the right to make, from time to time, revisions to the anticipated product life cycle plan
for a product to accommodate changes in production capabilities, alternative product availabilities, or market demand. The
information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, Inc. assumes no respon-
sibility for its use; nor for any infringements of patents or other rights of third parties which may result from its use.
A5350
Ionization Smoke Detector with Interconnect
Features and Benefits
▪
Low average standby current for long battery life
▪
Interconnect up to 125 detectors
▪
Piezoelectric horn driver
▪
Guard outputs for detector input
▪
Pulse testing for low battery
▪
Power-on reset (POR)
▪
Internal reverse battery protection
▪
Inverted alarm polarity on DETECT IN
Description
The A5350 is a low-current, BiCMOS 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 their alarm. In addition, special features are
incorporated to facilitate alignment and test of the finished
smoke detector.
The internal oscillator and timing circuitry keep standby power
to a minimum by powering down the device for 1.66 seconds
and sensing for smoke for only 10 ms. Every 24 on-off cycles,
a check is made for a 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 A5350 is supplied in a low-cost 16-pin dual in-line plastic
package (DIP). It is rated for continuous operation over the
temperature range of –10°C to 60°C. The Pb (lead) free version
(suffix –T) has 100% matte tin leadframe plating.
Package: 16-pin DIP (suffix A):
Not to scale
Typical Application
A
Use an external resistor divider to set
sensitivity for a particular smoke chamber.
B
A resistor to VSS or VDD may
be added to this pin to modify
low battery voltage threshold.
C
Value of component will vary, based on
the piezoelectric horn used.
1 NC
200
Ω
To / from
other units
GUARD2
DETECT IN
16
15
14
200 k
Ω
Push
to Test
2
3
I/O
A5350
LOW-V SET
GUARD1
SENSITIVITY SET
B
4.7 MΩ
4 NC
330
Ω
9V
13
12
200 k
Ω
A
4.7 MΩ
5
6
LED
VDD
TIMING RES
FEEDBACK
OSC CAP
HORN2
HORN1
VSS
0.1
μF
11
10
9
1.5 MΩ
C
220 kΩ
C
8.2 MΩ
1
μF
7
8
0.001
μF
C
26110.5 Rev. 5
A5350
Selection Guide
Part Number
A5350CA-T*
A5350CA
Pb-Free
Yes
–
Ionization Smoke Detector with Interconnect
Packing
25 pieces per tube
*Variant is in production but has been determined to be NOT FOR NEW DESIGN. This classifi-
cation indicates that sale of the variant is currently restricted to existing customer applications.
The variant should not be purchased for new design applications because obsolescence in the
near future is probable. Samples are no longer available. Status change: May 4, 2009.
Absolute Maximum Ratings*
Characteristic
Symbol
Notes
Rating
Units
Supply Voltage Range
Input Voltage Range
Reverse Battery Condition Duration
Input Current
Operating Ambient Temperature
Junction Temperature
Storage Temperature Range
V
DD
V
IN
t
RBAT
I
IN
T
A
T
J
(max)
T
stg
Referenced to V
SS
Referenced to V
SS
10.5 V
–0.5 to 15
–0.3 to V
DD
+ 0.3
20
10
–10 to 60
150
–55 to 125
V
V
s
mA
ºC
ºC
ºC
* CAUTION:BiCMOS devices have input static protection but are susceptible to damage when exposed to extremely high static electrical charges.
Thermal Characteristics
Characteristic
Package Thermal Resistance
Symbol
R
θJA
Test Conditions*
4-layer PCB based on JEDEC standard
Value Units
38
ºC/W
*Additional thermal information available on Allegro website.
Terminal List Table
Number
1
Name
NC
I/O
LOW-V SET
NC
LED
VDD
TIMING RES
FEEDBACK
VSS
HORN1
HORN2
OSC CAP
SENSITIVITY SET
GUARD1
DETECT IN
GUARD2
Function
No connection
Input/output to interconnected detectors
Optionally used with a resistor to adjust low-battery
threshold
No connection
Output to drive visible LED
Positive supply voltage
Terminal for timing resistor, sets internal bias
(affects timing)
Input for driving piezoelectric horn
Negative supply voltage
Output for driving piezoelectric horn
Complementary output for driving piezoelectric horn
Terminal for charging/discharging an external
capacitor to run the oscillator
Used with a resistor divider to externally set
sensitivity for a specific chamber
Active guard 1 for detector input
Input from detector chamber
Active guard 2 for detector input
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
Pin-out Diagram
2
3
NC 1
I/O 2
LOW-V SET 3
NC 4
LED 5
VDD 6
TIMING RES 7
FEEDBACK 8
16 GUARD2
15 DETECT IN
14 GUARD1
13 SENSITIVITY SET
12 OSC CAP
11 HORN2
10 HORN1
9 VSS
4
5
6
7
8
9
10
11
12
13
14
15
16
2
A5350
Ionization Smoke Detector with Interconnect
Functional Block Diagram
I/O
+Supply
9V
VDD
Band
Gap
V
DD
FEEDBACK
LBSamp
600 kΩ
Low Battery
Sample
HORN2
HORN1
Low Battery
Comparator
_
Logic
LOW-V SET
500 kΩ
+
_
Smoke
Comparator
Smoke
Sample
1.1 MΩ
LBSamp
SSamp
Oscillator
and Timing
Power-on
Reset
+
LED
+ V
DD
SENSITIVITY SET
SSamp
TIMING RES
+ V
DD
OSC CAP
-Supply
VSS
+
_
GUARD1
DETECT IN
GUARD2
+ V
DD
ION CHAMBER
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
3
A5350
Ionization Smoke Detector with Interconnect
ELECTRICAL CHARACTERISTICS
1,2
at T
A
= 25°C, V
DD
= 9.0 V, V
SS
= 0 V, C
OSCCAP
= 0.1
μF,
R
TIMINGRES
= 8.2 MΩ (unless otherwise noted)
Characteristic
Supply Voltage Range
Supply Current
Detector Input Current
Input Offset Voltage
Symbol
V
DD
I
DD
I
DETECTIN
V
OS(GUARD1)
V
OS(GUARD2)
V
OS
V
CM(guard)
V
CM
Z
AG1
Z
AG2
t
osc
t
osc(alarm)
t
w(osc)
V
DD(th)
V
OL
Horn Output Voltage
V
OH
Horn Output On-Time
Horn Output Off-Time
LED Output-On Current
LED Output On-Time
t
on(horn)
t
w(horn)
t
off(horn)
t
horn
I
LED
t
w(LED)
t
LED1
t
LED3
t
LED4
Test Conditions
Operating
V
DD
= 9.0 V, no alarm, no loads
V
DD
= 12 V, no alarm, no loads
0% to 40% RH, V
IN
= 0 to 9.0 V
Active GUARD1
Active GUARD2
Detect comparator
Guard amplifier
Smoke comparator
GUARD1 to VSS
GUARD2 to VSS
No alarm
Local or remote alarm
T
A
= 0°C to 50°C,
LOW-V SET open circuit
I
OUT
= 16 mA, V
DD
= 9.0 V
I
OUT
= 16 mA, V
DD
= 7.2 V
I
OUT
= –16 mA, V
DD
= 9.0 V
I
OUT
= –16 mA, V
DD
= 7.2 V
Local or remote alarm
Low battery
Local or remote alarm
Low battery
V
DD
= 7.2 V, V
LED
= 1.0 V
No alarm, in standby
Local alarm or test alarm
Remote alarm, no local smoke
Test Pin
6
6
6
15
14, 15
16, 15
15, 13
14, 15
13, 15
14
16
12
12
12
6
10, 11
10, 11
10, 11
10, 11
10,11
10, 11
10, 11
10, 11
5
5
5
5
5
Min.
6.0
—
—
—
—
—
—
2.0
0.5
—
—
1.34
37.50
8.0
7.2
—
—
8.5
6.3
120
8.0
60
32
10
8.0
32
0.76
—
Typ.
9.0
5.0
—
—
—
—
—
—
—
10
500
1.67
41.67
10
—
0.1
—
8.8
—
160
10
80
40
—
10
40
0.97
No LED
pulses
Max.
12
9.0
12
±1.0
±100
±100
±50
V
DD
– 0.5
V
DD
– 2.0
—
—
2.00
45.84
12
7.8
0.5
0.9
—
—
208
12
104
48
—
12
48
1.14
—
Units
V
μA
μA
pA
mV
mV
mV
V
V
kΩ
kΩ
s
ms
ms
V
V
V
V
V
ms
ms
ms
s
mA
ms
s
s
s
Common Mode Range
Active Guard Impedance
Oscillator Period
Oscillator Pulse Width
Low-Battery Threshold
LED Output Off-Time
Continued on the next page…
Allegro MicroSystems, Inc.
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
4
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