Document Number: MC146012

Rev. 1.0, 5/2007

Freescale Semiconductor

Technical Data

© Freescale Semiconductor, Inc., 2007. All rights reserved.

Low Power CMOS Photoelectric

Smoke Detector IC

The MC146012 is an advanced smoke detector component containing

sophisticated very-low power analog and digital circuitry. The IC, when used with

an infrared photoelectric chamber and a small number of external components,

will detect smoke by sensing scattered light from smoke particles. When

detection occurs, a pulsating alarm is sounded via on-chip push-pull drivers and

an external piezoelectric transducer.

The MC146012 provides both audible and visual alarms. Upon sensing a

normal smoke level, both alarms will be activated. It is possible to mute the

audible alarm for approximately eight minutes through the Integrated Mute

Function (IMF), although the LED will continue to flash at a high rate. This feature

is resetable through a pushbutton test. The IMF feature will be overridden by

remote smoke, high smoke level, timeout or reset.

The Alarm memory feature will allow for identification of an alarming detector.

Through a pushbutton test, the LED will flash rapidly if there was a previous

alarm condition detected at the unit.

The variable-gain photo amplifier allows direct interface to IR detector

(photodiode). The gain settings are determined by external capacitors and

compensation resistors. A two stage speed-up is incorporated into the smoke

monitor to minimize time and help reduce false triggering. Further reduction of

false triggering is also addressed with the double sample chamber sensitivity and

double I/O sample.

Features

•

Integrated Mute Function (IMF) to Temporarily Disable Horn

•

Alarm Memory to Help Identify Alarming Unit

•

Speed-Up Sampling Rate After First Detection of Smoke

•

Double Sample for Degraded Chamber Sensitivity Monitor

•

Digital Noise Filter on the I/O Pin

•

Power-Up and Power-Down RESET

•

Low-Battery Trip Point Set Externally

•

Temporal Horn Pattern

•

Operating Temperature: -10 to 75°C

•

Operating Voltage Range: 6.0 to 12 V

•

Average Supply Current: 6.5

µA

ORDERING INFORMATION

Device

Temp. Range

Package

MC146012ED

-10 to 75°C

Plastic Dip

MCZ146012EG/R2

SOIC Package

MC146012

LOW POWER CMOS

PHOTOELECTRIC SMOKE

DETECTOR IC

16

1

ED SUFFIX

PLASTIC DIP

98ASB42431B

16

EG SUFFIX

SOIC PACKAGE

98ASB42567B

1