A5338
Package A
, 16-lead DIP
Smoke Detector
with Interconnect and Timer
The A5338CA 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 facili-
tate alignment and test of the finished smoke detector.
This device is designed to comply with Underwriters
Laboratories Specification UL217.
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 A5338CA 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.
Approximate Scale 1:1
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 and control for reduced sensitivity
Built-in hysteresis reduces false triggering
Typical Application
9V
50 kΩ
200 k
Ω
200 kΩ
Push to set
1
To other units
200
Ω
2
3
+SUPPLY or
–SUPPLY
RLV
16
Push to test
TIMER START
I/O
LOW-V SET
GUARD2
Smoke
Chamber
DETECT IN 15
A5338
GUARD1 14
13
12
11
COSC
0.1
μ
F
RS
+SUPPLY or
–SUPPLY
4 TIMER OUT
5
330
Ω
6
RT
8.2 M
Ω
7
8
LED
+SUPPLY
TIMING RES
FEEDBACK
SENSIVITIVTY SET
OSC CAP
HORN2
HORN1 10
–SUPPLY
9
1 MΩ
200 kΩ
Horn
1
μF
0.001
μF
RST
Dwg. EC-005A
26110.1
ALLEGRO [ ALLEGRO MICROSYSTEMS ]
