RE46C145
CMOS Photoelectric Smoke Detector ASIC with Interconnect
and Timer Mode
Features:
•
•
•
•
•
•
•
•
•
•
Internal Power On Reset
Low Quiescent Current Consumption
ESD Protection on all Pins
Interconnect up to 40 Detectors
10 Minute Timer for Sensitivity Control
Temporal Horn Pattern
Internal Low Battery and Chamber Test
Compatible with Allegro A5366
Alternate Diagnostic Mode
UL Recognized per File S24036
General Description:
The RE46C145 is a low-power, CMOS photoelec-
tric-type smoke detector IC. With minimal external
components, this circuit will provide all the required fea-
tures 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 100 µs every 10 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.
In diagnostic mode, the photo amplifier output is avail-
able on pin 15 for production calibration of the photo
chamber.
When in Standby, a check for a low battery condition
and chamber integrity is performed every 43 seconds.
The temporal horn pattern supports the NFPA 72
emergency evacuation signal.
An interconnect pin allows multiple detectors to be con-
nected such that when one units alarms, all units will
sound.
An internal 10 minute timer can be used for a reduced
sensitivity mode.
The RE46C145 is recognized by Underwriters
Laboratories for use in smoke detectors that comply
with specification UL217 and UL268.
Package Types
RE46C145
PDIP, SOIC, SOICN
C1
C2
DETECT
STROBE
V
DD
IRED
IO
HORNB
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
TEST
VSEN
V
SS
ROSC
COSC
LED
FEED
HORNS
2009-2012 Microchip Technology Inc.
DS22181C-page 1
RE46C145
Functional Block Diagram
VDD (5)
+
-
Horn Driver
+
-
VSEN (15)
Smoke Comparator
Logic and
Timing
HB (8)
LED (11)
V
DD
-3.5V
PHOTOAMP
DETECT (3)
C1 (1)
+
-
Bias and
Power Reset
Low Battery
IO (7)
FEED (10)
HS (9)
IRED (6)
C2 (2)
Oscillator
V
DD
-5V
ROSC (13)
COSC (12)
STROBE (4)
TEST (16)
VSS (14)
Typical Application
9V
Battery
C3
1 μF
R
ADJ1
R2
5k
R3
8.2k
C1
.047 μF
C2
4700 pF
Push-to-Test
1
R4
16
15
14
R9
R12
10M
C5
1.5nF
D3
2
560
R
ADJ2
R1
4.7k
D6
R5
250k
3
4
5
13
100k
12
11
10
9
C6
1.0nF
R10
1.5M
R11
220k
R13
330
R6
1k
D5
C4
100 μF
R7
22
Q3
6
7
8
Smoke Chamber
To Other Units
R8
100
Note 1:
2:
3:
C3 should be located as close as possible to the device power pins.
C3 is typical for an alkaline battery. This capacitance should be increased to 4.7 µF or greater for a carbon battery.
R10, R11 and C6 are typical values and may be adjusted to maximize sound pressure.
DS22181C-page 2
2009-2012 Microchip Technology Inc.
RE46C145
1.0
1.1
ELECTRICAL
CHARACTERISTICS
Absolute Maximum Ratings†
V
DD
....................................................................................15V
Input Voltage Range Except FEED, IO .......... V
IN
= -.3V to V
DD
+.3V
FEED Input Voltage Range ..................... V
INFD
=-10 to +22V
IO Input Voltage Range................................. V
IO1
= -.3 to 15V
Input Current except FEED ................................... I
IN
= 10 mA
Operating Temperature ................................T
A =
-25 to +75°C
Storage Temperature ............................T
STG
= -55 to +125°C
Maximum Junction Temperature ......................... T
J
= +150°C
† Notice:
Stresses above those listed under “Maximum
ratings” may cause permanent damage to the device.
This is a stress rating only and functional operation of
the device at these or any other conditions above those
indicated in the operation listings of this specification is
not implied. Exposure to maximum rating conditions for
extended periods may affect device reliability.
DC ELECTRICAL CHARACTERISTICS
DC Electrical Characteristics:
Unless otherwise indicated, all parameters apply at T
A
= -25°C to +75°C, V
DD
= 9V
Parameter
Supply Voltage
Supply Current
Symbol
V
DD
I
DD1
Test
Pin
5
5
Min
6
—
Typ
—
4
Max
12
6
Units
V
µA
Conditions
Operating
Configured as in
Typical
Application,
COSC = V
SS
,
LED off
Configured as in
Typical
Application,
V
DD
= 12V,
COSC = V
SS
Configured as in
Typical
Application,
STROBE on,
IRED off, V
DD
=12V
Configured as in
Typical
Application,
STROBE on,
IRED on, V
DD
= 12V,
Note 1
FEED
No Local Alarm, IO as Input
V
SEN
TEST
FEED
No Local Alarm, IO as Input
V
SEN
TEST
V
DD
= 12V, COSC = 12V,
STROBE active
V
DD
= 12V, V
IN
= V
SS
V
DD
= 12V, V
IN
= V
SS
FEED = -10V
I
DD2
5
—
5.5
8
µA
I
DD3
5
—
—
2
mA
I
DD4
5
—
—
3
mA
Input Voltage High
V
IH1
V
IH2
V
IH3
V
IH4
10
7
15
16
10
7
15
16
1,2,3
10,12
15,16
10
6.2
3.2
1.6
8.5
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
2.7
1.5
.5
7
-100
-100
-1
-50
V
V
V
V
V
V
V
V
nA
nA
µA
µA
Input Voltage Low
V
IL1
V
IL2
V
IL3
V
IL4
Input Leakage Low
I
IL1
I
IL2
I
IL3
I
LFD
Note 1:
2:
3:
4:
Does not include Q3 emitter current.
Not production tested.
Typical values are for design information and are not ensured.
Limits over the specified temperature range are not production tested and are based on characterization
data.
2009-2012 Microchip Technology Inc.
DS22181C-page 3
RE46C145
DC ELECTRICAL CHARACTERISTICS (CONTINUED)
DC Electrical Characteristics:
Unless otherwise indicated, all parameters apply at T
A
= -25°C to +75°C, V
DD
= 9V
Parameter
Input Leakage High
Symbol
I
IH1
I
IH2
I
HFD
Input Pull Down Current
I
PD1
I
PD2
I
PDIO1
I
PDIO2
Output Leakage
Current Low
Output Leakage
Current High
Output Voltage Low
I
OZL1
I
OZH1
V
OL1
V
OL2
V
OL3
Output Voltage High
Output Current
V
OH1
I
IOH1
I
IODMP
Low Battery
Alarm Voltage
Output Voltage
V
LB
V
STOF
V
STON
V
IREDOF
V
IREDON
Common Mode Voltage
V
CM1
Test
Pin
1,2
3,10,12
10
16
15
7
7
11,13
11,13
8,9
13
11
8,9
7
7
5
4
4
6
6
1,2,3
Min
—
—
—
.25
.1
20
—
—
—
—
—
—
5.5
-4
5
6.9
V
DD
–.1
V
DD
–
5.25
—
2.85
.5
Typ
—
—
—
—
.25
—
—
—
—
—
.5
—
—
—
—
7.2
—
-16
—
7.5
—
Max
100
100
50
10
.5
80
140
-1
1
1
—
.6
Units
nA
nA
µA
µA
µA
µA
µA
µA
µA
V
V
V
V
mA
mA
V
V
V
V
V
V
STROBE off, V
DD
= 12V,
I
OUT
= -1 µA
STROBE on, V
DD
= 9V
I
OUT
= 100 µA to 500 µA
IRED off, V
DD
= 12V,
I
OUT
= 1 µA
IRED on, V
DD
= 9V
I
OUT
= 0 to -6 mA, T
A
= +25°C
Local smoke,
Push to Test or Chamber Test,
Note 2
Internal Reference
Conditions
V
DD
= 12V, V
IN
= V
DD
,
STROBE active
V
DD
= 12V, V
IN
= V
DD
FEED = 22V
V
IN
= V
DD
V
IN
= V
DD
V
IN
= V
DD
V
IN
= 15V, V
DD
= 12
Output Off, Output = V
SS
Output Off, Output = V
DD
Iol = 16 mA, V
DD
= 6.5V
Iol = 5 mA, V
DD
= 6.5V
Iol = 10 mA, V
DD
= 6.5V
Iol = -16 mA, V
DD
= 6.5V
Alarm, V
IO
= V
DD
–2V or
V
IO
= 0V
At Conclusion of Local Alarm
or Test, VV
IO
= 1V
V
DD
–5 V
DD
–4.75
—
3.1
—
.1
3.35
V
DD
–2
Smoke Comparator
Reference
Temperature Coefficient
V
REF
T
CST
T
CIRED
-
4
6
4,5
6,5
V
DD
–3.7
—
—
—
—
—
.01
.3
-50
-30
V
DD
–3.3
—
—
—
—
V
%/ºC V
DD
= 6V to 12V,
STROBE Output Voltage
%/ºC V
DD
= 6V to 12V,
IRED Output Voltage
dB
dB
Active, V
DD
=6V to 12V
Active, V
DD
= 6V to 12V
Line Regulation
Note 1:
2:
3:
4:
V
STON
V
IREDON
Does not include Q3 emitter current.
Not production tested.
Typical values are for design information and are not ensured.
Limits over the specified temperature range are not production tested and are based on characterization
data.
DS22181C-page 4
2009-2012 Microchip Technology Inc.
RE46C145
AC ELECTRICAL CHARACTERISTICS
AC Electrical Characteristics:
Unless otherwise indicated, all parameters apply at T
A
= -25°C to +75°C, V
DD
= 9V,
V
SS
= 0V, Component Values from
Typical Application;
R
9
= 100 K, R
12
= 10 M, C
5
= 1.5 nF
Parameter
Oscillator Period
LED and STROBE
On Time
LED Period
Symbol
T
POSC
T
ON1
T
PLED1
T
PLED2
T
PLED3
T
PLED4
STROBE
and IRED Pulse
Period
T
PER1
T
PER1A
T
PER1B
T
PER2
T
PER3
T
PER4
T
PER5
IRED On Time
Horn On Time
T
ON2
T
HON1
T
HON2
Horn Off Time
T
HOF1
T
HOF2
T
HOF3
IO Charge
Dump Duration
IO Delay
IO Filter
T
IODMP
T
IODLY1
T
IOFILT
Test
Pin
12
11,4
11
11
11
11
4,6
4,6
4,6
4,6
4,6
4,6
4,6
6
8,9
8,9
8,9
8,9
8,9
7
7
7
9.6
1.8
.9
.9
7.2
300
39
94
450
9.5
450
1.35
39
.9
0
600
104
500
10.5
500
1.5
43
Min
9.4
9.4
39
.45
9.6
Typ
10.5
10.5
43
.5
10.75
10.75
2
1
1
8
336
LED IS NOT ON
11.8
2.2
1.1
1.1
8.9
370
47
115
550
11.5
550
1.65
47
1.46
Max
11.5
11.5
47
.55
11.8
Units
ms
ms
s
s
s
s
s
s
s
s
s
ms
s
µs
ms
ms
ms
s
s
s
s
mSs
Test Conditions
No alarm condition
Operating
Standby, no alarm
Local alarm condition
Timer mode, no local alarm
Remote alarm only
Standby, no alarm
Standby, after one valid smoke
sample
Standby, after two consecutive
valid smoke samples
In Local Alarm (three consecu-
tive valid smoke samples)
In Remote Alarm
Push-button test
Chamber Test or Low Battery
Test, no alarms
Operating
Operating, alarm condition,
Note 1
Low Battery or Failed Chamber
test , no alarm
Operating, alarm condition,
Note 1
Operating, alarm condition,
Note 1
Low Battery or Failed Chamber
test, no alarm
At the conclusion of the Local
Alarm or Test
From start of Local Alarm to
IO Active
IO pulse-width ensured to be
filtered. IO as input, no local
alarm
No local alarm, from IO Active
to Horn Active
No alarm condition,
Note 2
Remote
Alarm Delay
Timer Period
Note 1:
2:
3:
4:
T
IODLY2
T
TPER
7
1.05
7
8.5
2.0
10
s
Min
See timing diagram for Horn Temporal Pattern
During the Timer mode, the LED period is 10.5 seconds. The LED period will return to 43 seconds at the
conclusion of the Timer mode.
T
POSC
and T
ON2
are 100% production tested. All other timing is ensured by functional testing.
Typical values are for design information and are not ensured.
2009-2012 Microchip Technology Inc.
DS22181C-page 5
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