R&E International
A Subsidiary of Microchip Technology Inc.
RE46C122
CMOS Ionization Smoke Detector ASIC with Interconnect and Timer Mode
Product Specification
General Description
The RE46C122 is low power CMOS ionization type
smoke detector IC. With few external components this
circuit will provide all the required features for an
ionization type smoke detector.
An internal oscillator strobes power to the smoke
detection circuitry for 10.5mS every 1.66 seconds to
keep standby current to a minimum. A check for a low
battery condition is performed every 40 seconds when
in standby. The temporal horn pattern supports the
NFPA 72 emergency evacuation signal.
An interconnect pin allows multiple detectors to be
connected such that when one units alarms all units will
sound.
© 2009 Microchip Technology Inc. DS22173B-page 1
An internal 10 minute timer allows for a separate button
to be used for reduced sensitivity mode.
Although this device was designed for smoke detection
utilizing an ionization chamber it could be used in a
variety of security applications.
The RE46C122 is recognized by Underwriters
Laboratories for use in smoke detectors that comply
with specification UL217 and UL268.
Features
• >1500V ESD Protection (HBM) on all Pins
• Guard Outputs for Ion Detector Input
• +/-0.75pA Detect Input Current
• Internal Reverse Battery Protection
• Low Quiescent Current Consumption (<6.5uA)
• Available in 16L PDIP or 16L N SOIC
• Internal Low Battery Detection
• Power Up Low Battery Test
• Interconnect up to 40 Detectors
• 10 Minute Timer for Sensitivity Control
• Compatible with Allegro A5367
• UL Recognized per File S24036
• Available in Standard Packaging or RoHS
Compliant Pb Free Packaging.
Pin Configuration
16
1
GUARD2
TSTART
2
DETECT IO
15
3
GUARD1LBADJ
14
TSTROBE
4
VSEN
13
ABSOLUTE MAXIMUM RATINGS
PARAMETER SYMBOL VALUE UNITS
Supply Voltage V
DD
15 V
Input Voltage Range Except FEED, IO V
in
-.3 to V
dd
+.3 V
FEED Input Voltage Range V
infd
-10 to +22 V
IO Input Voltage Range V
io1
-.3 to 17 V
Reverse Battery Time T
RB
5 S
Input Current except FEED I
in
10 mA
Operating Temperature T
A
-10 to 60
°C
Storage Temperature T
STG
-55 to 125
°C
Maximum Junction Temperature T
J
150
°C
Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress
ratings only and operation at these conditions for extended periods may affect device reliability.
This product utilizes CMOS technology with static protection; however proper ESD prevention procedures should be used when
handling this product. Damage can occur when exposed to extremely high static electrical charge.
OSCAP
5
12
LED
VDD
RBIAS
FEED
6
HS
11
7
HB
10
VSS
8 9
