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.
26110.5 Rev. 5
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
Ionization Smoke Detector with Interconnect
Typical Application
A5350
A5350
NC
I/O
LOW-V SET
NC
LED
VDD
TIMING RES
FEEDBACK
GUARD2
DETECT IN
GUARD1
SENSITIVITY SET
OSC CAP
HORN2
HORN1
VSS
To / from
other units
9
10
11
12
13
14
15
16
200 kΩ
200 Ω
8.2 MΩ
1 μF
0.1 μF
1.5 MΩ
4.7 MΩ
200 k Ω
220 k
Ω
Push
to Test
0.001 μF
330 Ω
9 V
B
C
C
C
A
B
Use an external resistor divider to set
sensitivity for a particular smoke chamber.
C
A resistor to VSS or VDD may
be added to this pin to modify
low battery voltage threshold.
Value of component will vary, based on
the piezoelectric horn used.
1
2
3
4
5
6
7
8
4.7 MΩ
A
Package: 16-pin DIP (suffix A):
Not to scale
