5358 Datasheet, PDF (1/12 Pages) Allegro MicroSystems – PHOTOELECTRIC SMOKE DETECTOR WITH INTERCONNECT AND TIMER

5358
PHOTOELECTRIC SMOKE DETECTOR
WITH INTERCONNECT AND TIMER
C1 1
C2 2
DETECT 3
STROBE 4
+ SUPPLY 5 V_DD
IRED 6
I/O 7
HORN1 ⁸
16 TEST
15 HUSH
V_SS 14 – SUPPLY
OSC. &
TIMING
13 TIMING RES.
12 OSC. CAP.
LOGIC
11 LED
HORN
DRIVER
10 FEEDBACK
9 HORN2
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.
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 µs 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.
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
Always order by complete part number: A5358CA .