MICROCHIP RE46C140

R&E International
A Subsidiary of Microchip Technology Inc.
RE46C140
CMOS Photoelectric Smoke Detector ASIC with Interconnect and Timer Mode
Product Specification
General Description
Features
The RE46C140 is low power CMOS photoelectric type
smoke detector IC. With minimal external components
this circuit will provide 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.
An internal oscillator strobes power to the smoke
detection circuitry for 100us 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.
Internal Power On Reset
Low Quiescent Current Consumption
Available in 16L PDIP or 16L N SOIC
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
Available in Standard Packaging or RoHS
Compliant Pb Free Packaging.
Pin Configuration
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 such that when one units alarms, all units
will sound.
C1
1
16
TEST
C2
2
15
VSEN
3
14
VSS
STROBE
4
13
ROSC
VDD
5
12
COSC
IRED
6
11
LED
IO
7
10
FEED
HORNB
8
9
DETECT
An internal 10 minute timer can be used for a reduced
sensitivity mode.
Utilizing low power CMOS technology the RE46C140
was designed for use in smoke detectors that comply
with Underwriters Laboratory Specification UL217 and
UL268.
HORNS
ABSOLUTE MAXIMUM RATINGS
PARAMETER
Supply Voltage
Input Voltage Range Except FEED, IO
FEED Input Voltage Range
IO Input Voltage Range
Input Current except FEED
Operating Temperature
Storage Temperature
Maximum Junction Temperature
SYMBOL
VDD
Vin
Vinfd
Vio1
Iin
TA
TSTG
TJ
VALUE
15
-.3 to Vdd +.3
-10 to +22
-.3 to 17
10
-25 to 75
-55 to 125
150
UNITS
V
V
V
V
mA
°C
°C
°C
Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are
stress ratings only and operation at these conditions for extended periods may affect device reliability.
This product utilizes CMOS technology with static protection; however proper ESD prevention procedures should be used when
handling this product. Damage can occur when exposed to extremely high static electrical charge.
2009 © Microchip Technology Inc.
DS22179A-page 1
RE46C140
CMOS Photoelectric Smoke Detector ASIC with Interconnect
and Timer Mode
Product Specification
R&E International
A Subsidiary of Microchip Technology Inc.
DC Electrical Characteristics at TA = -25° to 75°C, VDD=9V, Typical Application (unless otherwise noted)
Parameter
Supply Voltage
Supply Current
Input Voltage High
Input Voltage Low
Input Leakage Low
Input Leakage High
Input Pull Down Current
Output Leakage Current
Low
Output Leakage Current
High
Symbol
Test
Pin
VDD
5
IDD1
5
IDD2
5
IDD3
5
IDD4
5
VIH1
Limits
Typ
Max
Test Conditions
Min
Units
6
10
Operating
Configured as in Figure 2,
COSC=VSS, LED off
Configured as in Figure 2, VDD=12V,
COSC=VSS
Configured as in Figure 2, STROBE
on, IRED off, VDD=12V
Configured as in Figure 2, STROBE
on, IRED on, VDD=12V, Note 1
FEED
6.2
VIH2
7
No Local Alarm, IO as an Input
3.2
V
VIH3
15
VSEN
1.6
V
VIH4
16
TEST
8.5
VIL1
10
FEED
VIL2
7
VIL3
12
V
4
6
uA
5.5
8
uA
2
mA
3
mA
4.5
V
V
4.5
2.7
V
No Local Alarm, IO as an Input
1.5
V
15
VSEN
.5
V
VIL4
16
7
V
IIL1
1,2,3
-100
nA
IIL2
12,10
TEST
VDD=12V, COSC=12V, STROBE
active
VDD=12V, Vin=VSS
-100
nA
IIL3
15,16
VDD=12V, Vin=VSS
-1
uA
ILFD
10
FEED=-10V
-50
uA
IIH1
1,2
VDD=12V, Vin=VDD, STROBE active
100
nA
IIH2
3,12,10
VDD=12V, Vin=VDD
100
nA
IHFD
10
FEED=22V
50
uA
IPD1
16
Vin=VDD
.25
10
uA
IPD2
15
Vin=VDD
.1
.5
uA
IPDIO1
7
Vin=VDD
20
IPDIO2
7
Vin=17V, VDD=12
IOZL1
11,13
IOZH1
11,13
.25
80
uA
140
uA
Output Off, Output=VSS
-1
uA
Output Off, Output=VDD
1
uA
Note 1: Does not include Q3 emitter current.
2009 © Microchip Technology Inc.
DS22179A-page 2
RE46C140
CMOS Photoelectric Smoke Detector ASIC with Interconnect
and Timer Mode
Product Specification
R&E International
A Subsidiary of Microchip Technology Inc.
DC Electrical Characteristics (continued) at TA= -25° to 75°, VDD=9V, Typical Application (unless
otherwise noted)
Parameter
Output Voltage Low
Symbol
Test
Pin
VOL1
8,9
Iol=16mA, VDD=6.5V
VOL2
13
Iol=5mA, VDD=6.5V
Test Conditions
Min
1
.5
VOL3
11
Iol=10mA, VDD=6.5V
Output Voltage High
VOh1
8,9
Iol=-16mA, VDD=6.5V
5.5
Output Current
IIOH1
7
-4
IIODMP
7
Alarm, Vio=Vdd-2V or Vio=0V
At Conclusion of Local Alarm or
Test, Vio=1V
VLB
5
VSTOF
4
VSTON
4
VIREDOF
6
VIREDON
6
VCM1
1,2,3
Vref
-
TCST
4
TCIRED
6
ΔVSTON
ΔVIREDON
Low Battery Alarm Voltage
Output Voltage
Common Mode Voltage
Smoke Comparator
Reference
Temperature Coefficient
Line Regulation
Internal Reference, Note 1
4,5
VDD=6V to 12V, STROBE Output
Voltage
VDD=6V to 12V, IRED Output
Voltage
Active, VDD=6V to 12V
6,5
Active, VDD=6V to 12V
-16
V
mA
mA
7.2
7.5
Vdd-.1
2.85
V
V
5
VDD 5.25
Units
V
.6
6.9
STROBE off, VDD=12V,
Iout=-1uA
STROBE on, VDD=9V
Iout= 100uA to 500uA
IRED off, VDD=12V, Iout=1uA
IRED on, VDD=9V
Iout=0 to -6mA, Ta=25C
Local smoke, Push to Test or
Chamber Test, Note 1
Limits
Typ
Max
V
V
VDD 5
3.1
VDD 4.75
.1
V
V
3.35
V
.5
VDD-2
V
VDD3.7
VDD3.3
V
.01
%/ºC
.3
%/ºC
-50
dB
-30
dB
Note 1: Not production tested
Typical values are for design information and are not guaranteed.
Limits over the specified temperature range are not production tested and are based on characterization data.
2009 © Microchip Technology Inc.
DS22179A-page 3
RE46C140
CMOS Photoelectric Smoke Detector ASIC with Interconnect
and Timer Mode
Product Specification
R&E International
A Subsidiary of Microchip Technology Inc.
AC Electrical Characteristics at TA =-25° to 75°, VDD=9V, VSS=0V, Component Values from Figure 2 ;
R9=100KΩ, R12=10MΩ, C5= 1.5nF(unless otherwise noted)
Parameter
Symbol
Test
Pin
TPOSC
12
Oscillator Period
LED and STROBE On Time
Min
Limits
Typ
Max
No Alarm Condition
9.4
10.5
11.5
mS
Test Conditions
Units
TON1
11,4
Operating
9.4
10.5
11.5
mS
TPLED1
11
Standby, No Alarm
39
43
47
S
TPLED2
11
Local Alarm Condition
.45
.5
.55
S
TPLED3
11
Timer Mode, No Local Alarm
9.6
10.75
11.8
S
TPLED4
11
Remote Alarm Only
TPER1
4,6
TPER1A
4,6
TPER1B
4,6
TPER2
4,6
TPER3
4,6
Standby, No Alarm
Standby, After 1 Valid Smoke
Sample
Standby, After 2 Consecutive Valid
Smoke Samples
In Local Alarm – (3 Consecutive
Valid Smoke Samples)
In Remote Alarm
TPER4
4,6
TPER5
4,6
IRED On Time
TON2
6
Pushbutton Test
Chamber Test or Low Battery
Test, no Alarms
Operating
Horn On Time
THON1
8,9
THON2
8,9
THOF1
8,9
THOF2
8,9
THOF3
8,9
TIODMP
7
TIODLY1
7
TIOFILT
7
TIODLY2
7
LED Period
STROBE and IRED Pulse
Period
Horn Off Time
IO Charge Dump Duration
IO Delay
IO Filter
Remote Alarm Delay
Timer Period
TTPER
LED IS NOT ON
S
9.6
10.75
11.8
S
1.8
2
2.2
S
.9
1
1.1
S
.9
1
1.1
S
7.2
8
8.9
S
300
336
370
mS
47.1
S
38.9
94
104
115
uS
Operating, Alarm Condition, Note 1
Low Battery or Failed Chamber
Test , No Alarm
Operating, Alarm Condition, Note 1
450
500
550
mS
9.5
10.5
11.5
mS
450
500
550
mS
Operating, Alarm Condition, Note 1
Low Battery or Failed Chamber
Test, No Alarm
At Conclusion of Local Alarm or
Test Alarm
From Start of Local Alarm to IO
Active
IO pulse width guaranteed to be
filtered. IO as Input, No Local
Alarm
No Local Alarm, From IO Active
Horn Active
No Alarm Condition, Note 2
1.35
1.5
1.65
S
39
43
47
S
1.46
S
.9
0
S
1.05
8
10
600
mS
2.0
S
12
Min
Note 1 – See timing diagram for Horn Temporal Pattern
Note 2 – During the timer mode the LED Period is 10.5 seconds. The LED period will return to a 43 seconds at the conclusion of the timer
mode.
Note 3 - TPOSC and TON2 are 100% production tested. All other timing is guaranteed by functional testing.
Typical values are for design information and are not guaranteed.
Limits over the specified temperature range are not production tested and are based on characterization data.
2009 © Microchip Technology Inc.
DS22179A-page 4
RE46C140
CMOS Photoelectric Smoke Detector ASIC with Interconnect
and Timer Mode
Product Specification
2009 © Microchip Technology Inc.
R&E International
A Subsidiary of Microchip Technology Inc.
DS22179A-page 5
RE46C140
CMOS Photoelectric Smoke Detector ASIC with Interconnect
and Timer Mode
Product Specification
R&E International
A Subsidiary of Microchip Technology Inc.
Functional Block Diagram
Figure 1
2009 © Microchip Technology Inc.
DS22179A-page 6
RE46C140
CMOS Photoelectric Smoke Detector ASIC with Interconnect
and Timer Mode
Product Specification
R&E International
A Subsidiary of Microchip Technology Inc.
PIN DESCRIPTIONS
PIN#
PIN NAME
1
C1
The capacitor connected to this pin sets the photo amplifier gain (high) for the
push-to-test and chamber sensitivity test. The size of this capacitor will depend
on the chamber background reflections. A=1+(C1/10) where C1 is in pF. The
gain should be <10000.
2
C2
The capacitor connected to this pin sets the photo amplifier gain (normal) during
standby. The value of this capacitor will depend on the smoke sensitivity
required. A=1+(C2/10) where C2 is in pF.
3
DETECT
Positive input to the photo amplifier. This input is normally connected to the
cathode of an external photo diode operated at zero bias.
4
STROBE
Regulated output voltage of VDD-5 which is active during a test for smoke. This
output is the negative side of the photo amplifier circuitry.
5
VDD
Connect to the positive supply voltage
6
IRED
Provides a regulated pulsed output voltage pre-driver for the infrared emitter.
This output usually drives the base of an NPN transistor.
7
IO
This bidirectional pin provides the capability to interconnect many detectors in a
single system. This pin has an internal pull-down device.
8
HB
This pin is connected to the metal electrode of a piezoelectric transducer.
9
HS
HS is a complementary output to HB and connects to the ceramic electrode of
the piezoelectric transducer.
10
FEED
11
LED
12
COSC
A capacitor connected to this pin with parallel resistor sets the internal clock low
time which is approximately the clock period.
13
ROSC
A resistor between this pin and pin 12 (COSC) sets the internal clock high time.
This also sets the IRED pulse width (100-200uS).
14
VSS
15
VSEN
In the timer mode this input pin can be used to set an external smoke
comparator reference.
16
TEST
This input is used to invoke two test modes and the timer mode. This input has
an internal pull-down.
2009 © Microchip Technology Inc.
DESCRIPTION
Usually connected to the feedback electrode through a current limiting resistor. If
not used this pin must be connected to VDD or VSS.
Open drain NMOS output used to drive a visible LED.
Connect to the negative supply voltage.
DS22179A-page 7
RE46C140
CMOS Photoelectric Smoke Detector ASIC with Interconnect
and Timer Mode
Product Specification
R&E International
A Subsidiary of Microchip Technology Inc.
Typical Application
Figure 2
Notes:
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 4.7uF or greater for a carbon battery.
3.
R10, R11 and C6 are typical values and may be adjusted to maximize sound pressure.
2009 © Microchip Technology Inc.
DS22179A-page 8
RE46C140
CMOS Photoelectric Smoke Detector ASIC with Interconnect
and Timer Mode
Product Specification
R&E International
A Subsidiary of Microchip Technology Inc.
CIRCUIT DESCRIPTION AND APPLICATION NOTES
Note: All timing references are nominal. See electrical characteristics for limits.
Standby Internal Timing – With the external components specified in the typical application figure for ROSC and
COSC the internal oscillator has a nominal period of 10mS. Normally the analog circuitry is powered down to
minimize standby current (typically 4uA at 9V). Once every 10 seconds the detection circuitry (normal gain) is
powered up for 10mS. Prior to completion of the 10mS period the IRED pulse is active for 100uS. At the
conclusion of this 10mS period the photo amplifier is compared to an internal reference to determine the chamber
status and latched. If a smoke condition is present the period to the next detection decreases and additional
checks are made. Three consecutive smoke detections will cause the device to go into alarm and the horn circuit
and interconnect will be active.
Once every 40 seconds the status of the battery voltage is checked. This status is checked and latched at the
conclusion of the LED pulse. In addition, once every 40 seconds the chamber is activated and using the high gain
mode (capacitor C1) a check of the chamber is made by amplifying background reflections. If either the low
battery or the photo chamber test fails the horn will chirp for 10mS every 40 seconds.
The oscillator period is determined by the values of R9, R12 and C5 (see typical application FIG 2). The oscillator
period T=TR+ TF where TR =.6931 * R12 * C5 and TF =.6931 * R9 * C5
Smoke Detection Circuitry – A comparator compares the photo amp output to an internal reference voltage. If the
required number of consecutive smoke conditions is met the device will go into local alarm and the horn will be
active. In local alarm the C2 gain is internally increased by ~10% to provide alarm hysteresis.
Push to Test Operation – If the TEST input pin is activated (Vih) then, after one internal clock cycle, the smoke
detection rate increases to once every 330mS. In this mode the high gain capacitor C1 is selected and
background reflections are used to simulate a smoke condition. After the required consecutive detections the
device will go into a local alarm condition. When the TEST input is deactivated (Vil) and after one clock cycle the
normal gain capacitor C1 is selected. The detection rate continues at once every 330mS until 3 consecutive no
smoke conditions are detected. At this point the device returns to standby timing.
LED Operation – In standby the LED is pulsed on for 10mS every 43 Seconds. In a local alarm condition or the
push to test alarm the LED pulse frequency is increased to once every .5 seconds. In the case of a remote alarm
the LED not active. In the timer mode of operation the LED is pulsed on for 10mS every 10 seconds.
Interconnect Operation – The bidirectional IO pin allows for interconnection of multiple detectors. In a local alarm
condition this pin is driven high immediately through a constant current source. Shorting this output to ground will
not cause excessive current. The IO is ignored as an input during a local alarm.
The IO pin also has an NMOS discharge device that is active for 1 second after the conclusion of any type of local
alarm. This device helps to quickly discharge any capacitance associated with the interconnect line.
If a remote active high signal is detected the device goes into remote alarm and the horn will be active. Internal
protection circuitry allows for the signaling unit to have a higher supply voltage than the signaled unit without
excessive current draw.
The interconnect input has a 670mS nominal digital filter. This allows for interconnection to other types of alarms
(carbon monoxide for example) that may have a pulsed interconnect signal.
2009 © Microchip Technology Inc.
DS22179A-page 9
RE46C140
CMOS Photoelectric Smoke Detector ASIC with Interconnect
and Timer Mode
Product Specification
R&E International
A Subsidiary of Microchip Technology Inc.
Low Battery and Chamber Test – In standby an internal reference is compared to the voltage divided VDD supply.
Low battery status is latched at the conclusion of the LED pulse. The horn will chirp for 10ms every 43 seconds
until the low battery condition no longer exists. In standby a chamber test is also performed every 40 seconds by
switching to the high gain capacitor C1 and sensing the photo chamber background reflections. Two consecutive
chamber tests failures will also cause the horn to chirp for 10mS every 43 seconds. The low battery chirp occurs
next to the LED pulse and the failed chamber test chirp ~20 seconds later. The low battery and chamber tests are
not performed in a local or remote alarm condition.
Timer Mode – If resistors Radj1 and Radj2 are in place and a high to low transition occurs on the TEST input the
device enters a 10 minute timer mode. In this mode the smoke comparator reference is switched from the internal
VDD-3.5V reference to the voltage that appears on VSEN (pin 15). This allows the sensitivity to be modified for
the duration of the 10 minute timer period. The chamber test is performed in the timer mode. If VSEN is left
unconnected or tied to VSS the timer mode of operation is inhibited.
Diagnostic Mode – In addition to the normal function of the TEST input a special diagnostic mode is available for
calibration and test of the smoke detector. Taking the TEST pin below VSS and sourcing ~300uA out of the pin
for 1 clock cycle will enable the diagnostic mode. In the diagnostic mode some of the pin functions are redefined.
Refer to the table below for redefined pin functions in the diagnostic mode. In addition in this mode STROBE is
always enabled and the IRED is pulsed at the clock rate of 10.5mS nominal.
Pin Name
IO
Pin Number
7
VSEN
15
FEED
10
COSC
HORNB
12
8
LED
11
Description
Disabled as an output. A high on this pin directs the photo amplifier output to pin C1
(1) or C2 (2), determined by the level on VSEN (15). Amplification occurs during the
IRED active time.
If IO is high then this pin controls the gain capacitor that is used. If VSEN is low then
normal gain is selected and the photo amp output appears on C1 (1). If VSEN is
high then high gain is selected and the photo amp output is on C2 (2).
If VSEN (15) is low then taking this input high will enable hysteresis which is a
nominal 10% gain increase in normal gain mode.
If desired this pin can be driven by an external clock.
This pin becomes the smoke integrator output. A high level indicates that an alarm
condition has been detected.
The LED pin is used as a low battery indicator. For VDD above the low battery
threshold the open drain NMOS is off. If VDD falls below the threshold the NMOS
turns on.
2009 © Microchip Technology Inc.
DS22179A-page 10
RE46C140
CMOS Photoelectric Smoke Detector ASIC with Interconnect
and Timer Mode
Product Specification
R&E International
A Subsidiary of Microchip Technology Inc.
Timing Diagrams
Standby, No Alarm (not to Scale)
Oscillator
TPOSC
TPWOSC
Internal Clock
TON1
TPER1
STROBE
TON2
IRED
TPLED1
LED
Low Supply or Chamber Test Failure
LED
THON3
Low BatteryTest
Low BatteryWarning Chirp
Low Battery Warning Chirp
Horn
THOF3
Chamber Test and Warning is Offset from Low Battery Test and Warning by 21.5 Seconds.
2009 © Microchip Technology Inc.
DS22179A-page 11
RE46C140
CMOS Photoelectric Smoke Detector ASIC with Interconnect
and Timer Mode
Product Specification
R&E International
A Subsidiary of Microchip Technology Inc.
Timing Diagrams (continued)
Local Alarm Timing (not to scale)
TPER2
STROBE
IRED
TPLED2
LED
No Alarm
Local or Remote Alarm
No Alarm
Horn Temporal Pattern
THON1
THOF1
THOF2
Horn
Interconnect Timing
TIODLY1
IO as Output
TIOFILT
TIODLY2
IO as Input
Notes:
1. Smoke is not sampled when the horn is active. Horn cycle is self completing in local alarm but not in remote alarm.
2. Low battery warning chirp is suppressed in local or remote alarm.
3. IO Dump active only in local alarm, inactive if external alarm.
2009 © Microchip Technology Inc.
DS22179A-page 12
RE46C140
CMOS Photoelectric Smoke Detector ASIC with Interconnect
and Timer Mode
Product Specification
Information contained in this publication regarding device
applications and the like is provided only for your convenience and
may be superseded by updates. It is your responsibility to ensure
that your application meets with your specifications. MICROCHIP
MAKES NO REPRESENTATIONS OR WARRANTIES OF ANY
KIND WHETHER EXPRESS OR IMPLIED, WRITTEN OR ORAL,
STATUTORY OR
OTHERWISE,
RELATED
TO
THE
INFORMATION, INCLUDING BUT NOT LIMITED TO ITS
CONDITION, QUALITY, PERFORMANCE, MERCHANTABILITY
OR FITNESS FOR PURPOSE. Microchip disclaims all liability
arising from this information and its use. Use of Microchip devices in
life support and/or safety applications is entirely at the buyer’s risk,
and the buyer agrees to defend, indemnify and hold harmless
Microchip from any and all damages, claims, suits, or expenses
resulting from such use. No licenses are conveyed, implicitly or
otherwise, under any Microchip intellectual property rights.
R&E International
A Subsidiary of Microchip Technology Inc.
Trademarks
The Microchip name and logo, the Microchip logo, Accuron,
dsPIC, KEELOQ, KEELOQ logo, MPLAB, PIC, PICmicro,
PICSTART, rfPIC, SmartShunt and UNI/O are registered
trademarks of Microchip Technology Incorporated in the U.S.A.
and other countries.
FilterLab, Hampshire, Linear Active Thermistor, MXDEV, MXLAB,
SEEVAL, SmartSensor and The Embedded Control Solutions
Company are registered trademarks of Microchip Technology
Incorporated in the U.S.A.
Analog-for-the-Digital Age, Application Maestro, CodeGuard,
dsPICDEM, dsPICDEM.net, dsPICworks, dsSPEAK, ECAN,
ECONOMONITOR, FanSense, In-Circuit Serial Programming,
ICSP, ICEPIC, Mindi, MiWi, MPASM, MPLAB Certified logo,
MPLIB, MPLINK, mTouch, nanoWatt XLP, PICkit, PICDEM,
32
logo, PowerCal, PowerInfo,
PICDEM.net, PICtail, PIC
PowerMate, PowerTool, REAL ICE, rfLAB, Select Mode, Total
Endurance, TSHARC, WiperLock and ZENA are trademarks of
Microchip Technology Incorporated in the U.S.A. and other
countries.
SQTP is a service mark of Microchip Technology Incorporated in
the U.S.A.
All other trademarks mentioned herein are property of their
respective companies.
© 2009, Microchip Technology Incorporated, Printed in the
U.S.A., All Rights Reserved.
Printed on recycled paper.
Microchip received ISO/TS-16949:2002 certification for its worldwide
headquarters, design and wafer fabrication facilities in Chandler and
Tempe, Arizona; Gresham, Oregon and design centers in California and
India. The Company’s quality system processes and procedures are for its
PIC® MCUs and dsPIC® DSCs, KEELOQ® code hopping devices, Serial
EEPROMs, microperipherals, nonvolatile memory and analog products. In
addition, Microchip’s quality system for the design and manufacture of
development systems is ISO 9001:2000 certified.
2009 © Microchip Technology Inc.
DS22179A-page 13