R&E International

A Subsidiary of Microchip Technology Inc.

RE46C122

CMOS Ionization Smoke Detector ASIC with Interconnect and Timer Mode

Product Specification

© 2009 Microchip Technology Inc.

DS22173A-page 1

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.

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.

Utilizing low power CMOS technology the RE46C122

was designed for use in smoke detectors that comply

with Underwriters Laboratory 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

•

Available in Standard Packaging or RoHS Compliant

Pb Free Packaging.

Pin Configuration

16

GUARD2

1

TSTART

2

DETECT

IO

15

3

GUARD1

LBADJ

14

TSTROBE

4

VSEN

13

ABSOLUTE MAXIMUM RATINGS

PARAMETER

SYMBOL

VALUE

UNITS

Supply Voltage

15

V

Input Voltage Range Except FEED, IO

V

FEED Input Voltage Range

-10 to +22

V

IO Input Voltage Range

-.3 to 17

V

Reverse Battery Time

5

S

Input Current except FEED

10

mA

Operating Temperature

-10 to 60

°C

Storage Temperature

-55 to 125

°C

Maximum Junction Temperature

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.

5

OSCAP

12

LED

VDD

RBIAS

FEED

6

HS

11

7

HB

10

VSS

8

9