Photoelectric Smoke Detector
with Interconnect and Timer
A5358
Timing Diagrams
(Not to Scale)
Standby Mode
tr(ired)
Test event
tf(ired)
OSC CAP Pin
90%
50%
10%
Internal Clock
tw(ired)
tosc
tst1, tired1
Photo Sample
tled1, tst5
Low-Battery Test
tst5, tired5
Chamber Test
tw(st)
STROBE Pin
IRED Pin
LED off (High-Z)
LED Pin
LED on
tw(led)
Low Battery Condition
VDD Pin
(Low battery)
Low-Battery Test
Failed “test period”
LED on
thorn
Horn Enable
LED Pin
tw(horn)
LED off
(High-Z)
Chirps occur at the end of a failed “test period,” and are nearly coincident with LED flashes
Degraded Chamber Condition
Chamber
Sensitivity
(Degraded chamber)
Chamber Test
Horn Enable
thorn
tw(horn)
LED off
(High-Z)
LED Pin
LED on
Chirps occur after 2 consecutive failed tests, and are offset from LED flashes and from chirps that indicate failure of low-battery tests
Allegro MicroSystems, LLC
115 Northeast Cutoff
10
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
ALLEGRO [ ALLEGRO MICROSYSTEMS ]
