General Description

The RE46C143 is low power 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 for 100us every 8.1 seconds to keep 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 and chamber integrity is performed every 40 seconds when in standby. The alarm horn pattern utilizes a 75 duty cycle.

An interconnect pin allows multiple detectors to be connected such that when one units alarms, all units will sound.

Utilizing low power CMOS technology the RE46C143 was designed for use in smoke detectors that comply with Underwriters Laboratory Specification UL217 and UL268.

Features

• Internal Power On Reset

• Low Quiescent Current Consumption

• Available in 16L PDIP or 16L N SOIC

• ESD Protection on all Pins

• Interconnect up to 40 Detectors

• 75 Duty Cycle Horn Pattern

• Low Battery and Chamber Test

• Compatible with Motorola MC145010

• Available in Standard Packaging or RoHS Compliant Pb Free Packaging.