RE46C165/6/7/8
CMOS Photoelectric Smoke Detector ASIC
with Interconnect, Timer Mode and Alarm Memory
Features
• Temporal Horn Pattern or Continuous Tone
• Alarm Memory
• Sensitivity Control Times:
- 9 minutes (RE46C165/6)
- 1.2 minutes (RE46C167/8)
• I/O Filter and Charge Dump
• Interconnect up to 40 Detectors
• Internal Power-on Reset
• >2000V ESD Protection (HBM) on All Pins
• Low Quiescent Current Consumption (<8 µA)
• Internal Low Battery Detection and Chamber Test
• RoHS Compliant Lead-Free Packaging
Description
The RE46C165/6/7/8 devices are low-power, CMOS
photoelectric type, smoke detector ICs. With minimal
external components, these circuits will provide all the
required features for a photoelectric type smoke
detector.
Each 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.
A check for a low battery condition and chamber
integrity is performed every 43 seconds when in
standby. The temporal horn pattern supports the
NFPA 72 emergency evacuation signal.
An interconnect pin allows multiple detectors to be
connected so when one unit alarms, all units will sound.
A charge dump feature will quickly discharge the
interconnect line when exiting a local alarm. The
interconnect input is also digitally filtered.
An internal timer allows for single button, push-to-test
to be used for a reduced sensitivity mode.
An alarm memory feature allows the user to determine
if the unit has previously entered a local alarm
condition.
Utilizing
low-power
CMOS
technology,
the
RE46C165/6/7/8 was designed for use in smoke
detectors that comply with Underwriters Laboratory
Specification UL217 and UL268.
2010 Microchip Technology Inc.
DS22251A-page 1
RE46C165/6/7/8
Package Types
RE46C165/6/7/8
PDIP, SOIC
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
Functional Block Diagram
V
DD
(5)
R1
276K
R2
124K
+
-
+
-
IO (7)
FEED (10)
HS (9)
Logic
and
Timing
V
SS
(14)
VSEN (15)
HB (8)
LED (11)
V
DD
– 3.5V
STROBE (4)
DETECT (3)
C1 (1)
C2 (2)
TEST (16)
Oscillator
V
DD
– 5V
Photoamp
+
-
Reference
Bias and
Power
Reset
IRED (6)
ROSC (13)
COSC (12)
DS22251A-page 2
2010 Microchip Technology Inc.
RE46C165/6/7/8
Typical Application
R
ADJ1
1.0M
R3
8.2k
C1 47 nF
R2
5k
R
ADJ2
120k
R1
4.7k
C2 4.7 nF R4
560
D6
R5
Photo
Chamber
249k
1 C1
2 C2
3 DETECT
4 STROBE
5 V
DD
R6
1k
C4
100 µF
D5
R7
22
Q3
6 IRED
7 IO
8 HORNB
To Other Units
R8
330
C7
10 µF
LED 11
FEED 10
HORNS 9
C6
(3)
1.0 nF
R10
(3)
1.5M
R11
(3)
220k
TEST 16
VSEN 15
V
SS
14
ROSC 13
COSC 12
R13
330
R9
100k
D3
C3
(1,2)
1 µF
9V
Battery
R12
10M
C5
1.5 nF
Push-to-Test
Note 1:
C3 should be located as close as possible to the device power pins.
2:
C3 is typical for an alkaline battery. This capacitance should be increased to 4.7 µF or greater for a
carbon battery.
3:
R10, R11 and C6 are typical values and may be adjusted to maximize sound pressure.
2010 Microchip Technology Inc.
DS22251A-page 3
RE46C165/6/7/8
NOTES:
DS22251A-page 4
2010 Microchip Technology Inc.
RE46C165/6/7/8
1.0
ELECTRICAL
CHARACTERISTICS
† 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 indi-
cated in the operation listings of this specification is not
implied. Exposure to maximum rating conditions for
extended periods may affect device reliability.
Absolute Maximum Ratings†
V
DD
...........................................................................12.5V
Input Voltage Range Except FEED, I/O .. V
IN
= -.3V to V
DD
+.3V
FEED Input Voltage Range ............... V
INFD
=-10 to +22V
I/O Input Voltage Range .......................... V
IO1
= -.3 to 15V
Input Current except FEED, TEST, VSEN ...... I
IN
= 10 mA
Input Current for FEED, VSEN....................... I
IN
= 500 µA
Operating Temperature ..........................T
A =
-25 to +75°C
Storage Temperature.......................T
STG
= -55 to +125°C
Maximum Junction Temperature ................... T
J
= +150°C
DC ELECTRICAL CHARACTERISTICS
DC Electrical Characteristics:
Unless otherwise indicated, all parameters apply at T
A
= -25° to +75°, V
DD
= 9V,
Typical Application (unless otherwise noted), V
SS
= 0V
Parameter
Supply Voltage
Supply Current
Symbol
V
DD
I
DD1
I
DD2
I
DD3
I
DD4
Test
Pin
5
5
5
5
5
Min
6
—
—
—
—
Typ
—
4
5.5
—
—
Max
12
6
8
2
3
Units
V
µA
µA
mA
mA
Conditions
Operating
COSC = V
SS
, LED off
COSC = V
SS
, LED off,
V
DD
= 12V
COSC = V
SS
,
STROBE on IRED off
COSC = V
SS
,
STROBE on, IRED on,
Note 1
FEED
No local alarm,
I/O as an input
VSEN
TEST
FEED
No local alarm,
I/O as an input
VSEN
TEST
V
DD
= 12V, COSC = 12V,
STROBE active
V
DD
= 12V, V
IN
= V
SS
V
DD
= 12V, V
IN
= V
SS
FEED = -10V
Input Voltage High
V
IH1
V
IH2
V
IH3
V
IH4
10
7
15
16
10
7
15
16
1, 2, 3
12, 10
15, 16
10
6.2
3.2
1.6
8.5
—
—
—
—
—
—
—
—
4.5
—
—
—
4.5
—
—
—
—
—
—
—
—
—
—
—
2.7
1.5
0.5
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:
Does not include Q3 emitter current.
Not production tested.
Production test at room temperature with guard banded limits.
2010 Microchip Technology Inc.
DS22251A-page 5
