A5358 查看數據表（PDF） - Allegro MicroSystems

零件编号

产品描述 (功能)

生产厂家

A5358

Photoelectric Smoke Detector with Interconnect and Timer

Allegro MicroSystems 

A5358

Photoelectric Smoke Detector

with Interconnect and Timer

increased to one pulse every OSC CAP cycle and the STROBE

pin is always active. To exit this mode, the TEST pin should be

floated, or returned to VSS, for at least one OSC CAP cycle.

Alarm Indications

Alarm conditions include: local smoke detection, a remote alarm,

low battery, or degraded chamber sensitivity. These are indicated

by a combination of horn and LED signals, which continue until

the alarm condition is resolved. A local alarm always overrides

a remote alarm, and a local or remote alarm will inhibit warning

signals for low battery or degraded chamber.

During a local or a remote alarm condition, the horn output is a

continuous modulated tone, nominally: 252 ms on, 84 ms off.

The visible LED distinguishes a local alarm from a remote alarm.

During a local alarm, the LED blinks every 0.67 s (nominally),

but during a remote alarm, the LED is disabled and does not blink.

The degraded-chamber test occurs periodically (nominally every

43 s). During this test, the gain of the photoamplifier is switched

to the high (supervisory) level, set by C1. The device expects

that the photodiode will receive enough reflected background

light in the chamber to cause an alarm condition. If a faulty, dirty,

or obstructed chamber prevents this for two consecutive tests,

the device signals degraded chamber with one short (nominally

10 ms) horn chirp every 43 s, essentially halfway between LED

flashes. The condition is resolved when the chamber is either

cleared or cleaned.

The low-battery test also occurs periodically (also nominally

every 43 s, but offset from the degraded-chamber test). Dur-

ing this test, the load of the LED is applied to the battery, and

a resistive divider off VDD is compared to an internal band-gap

reference. If VDD is below the threshold, the device signals low

battery with one short (nominally 10 ms) horn chirp every 43 s,

occurring almost simultaneously with the visible LED flash. The

condition is resolved when the battery is replaced.

Allegro MicroSystems, Inc.

9

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

Share Link: