2010 Microchip Technology Inc. DS22271A-page 1
RE46C190
Features
• Two AA Battery Operation
• Internal Power On Reset
• Low Quiescent Current Consumption
• Available in 16L N SOIC
• Local Alarm Memory
• Interconnect up to 40 Detectors
• 9 Minute Timer for Sensitivity Control
• Temporal or Continuous Horn Pattern
• Internal Low Battery and Chamber Test
• All Internal Oscillator
• Internal Infrared Emitter Diode (IRED) driver
• Adjustable IRED Drive current
• Adjustable Hush Sensitivity
• 2% Low Battery Set Point
Description
The RE46C190 is a low power, low voltage CMOS
photoelectric type smoke detector IC. With minimal
external components, this circuit will provide all the
required features 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 every 10 seconds, to keep the
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.
A check for a low battery condition is performed every
86 seconds, and chamber integrity is tested once every
43 seconds, when in Standby. The temporal horn pat-
tern supports the NFPA 72 emergency evacuation sig-
nal.
An interconnect pin allows multiple detectors to be
connected such that, when one unit alarms, all units will
sound.
An internal 9 minute timer can be used for a Reduced
Sensitivity mode.
Utilizing low power CMOS technology, the RE46C190
was designed for use in smoke detectors that comply
with Underwriters Laboratory Specification UL217 and
UL268.
PIN CONFIGURATION
RE46C190
SOIC
V
SS
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
IRED
V
DD
TEST
TEST2
IRP
IRN
RLED
LX
V
BST
HS
HB
IO
IRCAP
FEED
GLED
CMOS Low Voltage Photoelectric Smoke Detector ASIC
with Interconnect and Timer Mode
