R&E International

A Subsidiary of Microchip Technology Inc.

RE46C120

CMOS Ionization Smoke Detector ASIC

Product Specification

© 2009 Microchip Technology Inc.

DS22157A-page 1

General Description

The RE46C120 is a low power CMOS ionization type

smoke detector IC. With a 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 TONE input allows for selection of a

temporal pattern or a 2/3 duty cycle continuous tone.

The temporal horn pattern supports the NFPA 72

emergency evacuation signal.

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 RE46C120

was designed for use in smoke detectors that comply

with Underwriters Laboratory Specification UL217 and

UL268.

Features

•

Guard Outputs for Ion Detector Input

•

+/-0.75pA Detect Input Current

•

Internal Reverse Battery Protection

•

Internal Low Battery Detection

•

Pin Selectable Horn Pattern

•

Low Quiescent Current Consumption (<6.5uA)

•

16L PDIP

•

ESD Protection on all Pins

•

Compatible with MC145017, MC14467

•

Available in RoHS Compliant Pb Free Packaging

Pin Configuration

16

DETCOMP

GUARD2

1

2

DETECT

N/C

15

3

GUARD1

LBADJ

14

4

VSEN

TONE

13

ABSOLUTE MAXIMUM RATINGS

PARAMETER

SYMBOL

VALUE

UNITS

Supply Voltage

15

V

Input Voltage Range Except FEED

V

FEED Input Voltage Range

-10 to +22

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