RE46C145_12 Datasheet, PDF (1/26 Pages) Microchip Technology – CMOS Photoelectric Smoke Detector ASIC with Interconnect and Timer Mode

RE46C145
CMOS Photoelectric Smoke Detector ASIC with Interconnect
and Timer Mode
Features:
• Internal Power On Reset
• Low Quiescent Current Consumption
• ESD Protection on all Pins
• Interconnect up to 40 Detectors
• 10 Minute Timer for Sensitivity Control
• Temporal Horn Pattern
• Internal Low Battery and Chamber Test
• Compatible with Allegro A5366
• Alternate Diagnostic Mode
• UL Recognized per File S24036
General Description:
The RE46C145 is a low-power, CMOS photoelec-
tric-type smoke detector IC. With minimal external
components, this circuit will provide all the required fea-
tures for a photoelectric-type smoke detector.
The design incorporates a gain-selectable photo
amplifier for use with an infrared emitter/detector pair.
An internal oscillator strobes power to the smoke
detection circuitry for 100 µs every 10 seconds to keep
standby current to a minimum. If smoke is sensed, the
detection rate is increased to verify an Alarm condition.
A High Gain mode is available for push button chamber
testing.
In diagnostic mode, the photo amplifier output is avail-
able on pin 15 for production calibration of the photo
chamber.
When in Standby, a check for a low battery condition
and chamber integrity is performed every 43 seconds.
The temporal horn pattern supports the NFPA 72
emergency evacuation signal.
An interconnect pin allows multiple detectors to be con-
nected such that when one units alarms, all units will
sound.
An internal 10 minute timer can be used for a reduced
sensitivity mode.
The RE46C145 is recognized by Underwriters
Laboratories for use in smoke detectors that comply
with specification UL217 and UL268.
Package Types
RE46C145
PDIP, SOIC, SOICN
C1 1
C2 2
DETECT 3
STROBE ₄
V_DD 5
IRED 6
IO 7
HORNB 8
16 TEST
15 VSEN
14 V_SS
13 ^ROSC
12 COSC
11 LED
10 FEED
9 HORNS
 2009-2012 Microchip Technology Inc.
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