Features

• Two AA Battery Operation

• Low Quiescent Current Consumption

• Local Alarm Memory

• Interconnect Up to 40 Detectors

• Nine-Minute Timer for Sensitivity Control

• Temporal or Continuous Horn Pattern

• Internal Low Battery and Chamber Test

• All Internal Oscillator

• Internal Infrared Emitter Diode (IRED) Driver

• Adjustable IRED Drive Current

• Adjustable Hush Sensitivity

• Two Percent Low Battery Set Point

• Pin-for-Pin Compatible with RE46C190

General Description

The RE46C191 is a low-power, low-voltage CMOS

photoelectric-type smoke detector IC. With minimal

external components, this circuit provides 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.

To keep the standby current to a minimum, an internal

oscillator strobes power to the smoke detection

circuitry every 10 seconds. 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 is performed every

86 seconds and the chamber integrity is tested once

every 43 seconds when in Standby mode. The temporal

horn pattern supports the NFPA 72 emergency

evacuation signal.

An interconnect pin allows multiple detectors to be

connected, such that when one unit alarms, all units

sound.

An internal nine-minute timer can be used for a

Reduced Sensitivity mode.

Package