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R&E International
A Subsidiary of Microchip Technology Inc.
RE46C146
CMOS Photoelectric Smoke Detector ASIC with Intelligent Interconnect and Timer Mode Product Specification
General Description
The RE46C146 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. In the diagnostic mode the photo amplifier output is available on pin 15 for production calibration of the photo chamber. A check for a low battery condition and chamber integrity is performed every 43 seconds when in standby. The temporal horn pattern for a smoke alarm condition 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. The interconnect is compatible with certain types of CO interconnect signaling and when recognized will sound the temporal pattern for a carbon monoxide alarm. An internal 10 minute timer can be used for a reduced sensitivity mode.
* * * * * * * * * * *
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 for Smoke and CO Internal Low Battery and Chamber Test Compatible with Allegro A5366 Alternate Diagnostic Mode Available in Standard Packaging or RoHS Compliant Pb Free Packaging
Pin Configuration
C1 C2 DETECT STROBE VDD IRED IO HORNB
1 2 3 4 5 6 7 8
16 15 14 13 12 11 10 9
TEST VSEN VSS ROSC COSC LED FEED HORNS
Utilizing low power CMOS technology the RE46C146 was designed for use in smoke detectors that comply with Underwriters Laboratory Specification UL217 and UL268.
Features
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 (c) 2009 Microchip Technology Inc. SYMBOL VDD Vin Vinfd Vio1 Iin TA TSTG TJ VALUE 12.5 -.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 DS22176A-page 1
RE46C146
CMOS Photoelectric Smoke Detector ASIC with Intelligent IO and Timer Mode Product Specification R&E International
A Subsidiary of Microchip Technology Inc.
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.
DC Electrical Characteristics at TA = -25 to 75C, VDD=9V, Typical Application (unless otherwise noted)
Parameter
Supply Voltage Supply Current
Symbol
VDD IDD1 IDD2 IDD3 IDD4
Test Pin
5 5 5 5 5 10 7 15 16 10 7 15 16 1,2,3 12 15,16 10 1,2 3,12 10 16 15 7 7 11,13 11,13
Test Conditions
Operating Configured as in Figure 2, COSC=VSS 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 FEED No Local Alarm, IO as an Input VSEN TEST FEED No Local Alarm, IO as an Input VSEN TEST VDD=12V, COSC=12V, STROBE active VDD=12V, Vin=VSS VDD=12V, Vin=VSS FEED=-10V VDD=12V, Vin=VDD, STROBE active VDD=12V, Vin=VDD FEED=22V Vin=VDD Vin=VDD Vin=VDD Vin=17V, VDD=12 Output Off, Output=VSS Output Off, Output=VDD
Min
6
Limits Typ Max
12 4 5.5 6 8 2 3
Units
V uA uA mA mA V V V V
Input Voltage High
VIH1 VIH2 VIH3 VIH4
6.2 3.2 1.6 8.5
4.5
Input Voltage Low
VIL1 VIL2 VIL3 VIL4
4.5
2.7 1.5 .5 7 -100 -100 -1 -50 100 100 50
V V V V nA nA uA uA nA nA uA uA uA uA uA uA uA
Input Leakage Low
IIL1 IIL2 IIL3 ILFD
Input Leakage High
IIH1 IIH2 IHFD
Input Pull Down Current
IPD1 IPD2 IPDIO1 IPDIO2
.25 .1 20 .25
10 .5 80 140 -1 1
Output Leakage Current Low Output Leakage Current High
IOZL1 IOZH1
(c) 2009 Microchip Technology Inc.
DS22176A-page 2
RE46C146
CMOS Photoelectric Smoke Detector ASIC with Intelligent IO 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
VOL1 VOL2 VOL3
Test Pin
8,9 13 11 8,9 7 7 5 4 4 6 6 1,2,3 4 6 4,5 6,5
Test Conditions
Iol=16mA, VDD=6.5V Iol=5mA, VDD=6.5V Iol=10mA, VDD=6.5V Iol=-16mA, VDD=6.5V Alarm, Vio=Vdd-2V or Vio=0V At Conclusion of Local Alarm or Test, Vio=1V 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 Internal Reference VDD=6V to 12V, STROBE Output Voltage VDD=6V to 12V, IRED Output Voltage Active, VDD=6V to 12V Active, VDD=6V to 12V
Min
Limits Typ Max
1 .5 1
Units
V V V V mA mA
Output Voltage High Output Current
VOh1 IIOH1 IIODMP
5.5 -4 5 6.9 11.9 VDD 5.3 2.25 .5 VDD3.85 .01 .3 -50 -30 VDD 5 3.1 VDD 4.7 .1 3.75 VDD-2 VDD3.15 7.2 7.5 -16
Low Battery Alarm Voltage Output Voltage
VLB VSTOF VSTON VIREDOF VIREDON
V V V V V V V %/C %/C dB dB
Common Mode Voltage Smoke Compare Reference Temperature Coefficient
VCM1 Vref TCST TCIRED
Line Regulation
VSTON VIREDON
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.
(c) 2009 Microchip Technology Inc.
DS22176A-page 3
RE46C146
CMOS Photoelectric Smoke Detector ASIC with Intelligent IO 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=100K, R12=10M, C5= 1.5nF(unless otherwise noted) Test Pin
12 11,4 11 11 11 11 4 4 4 4 4 4 6 8,9 8,9 8,9 8,9 8,9 8,9 8,9 8,9 7 7 7 7 7
Parameter
Oscillator Period LED and STROBE On Time LED Period
Symbol
TPOSC TON1 TPLED1 TPLED2 TPLED3 TPLED4
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 1 Valid Smoke Sample Standby, After 2 Consecutive Valid Smoke Samples In Local Alarm - (3 Consecutive Valid Smoke Samples) In Remote Alarm Pushbutton Test Operating Operating, Alarm Condition, Note 1 Low Battery or Failed Chamber Test , No Alarm Operating, CO Interconnect Alarm Condition, Note 1 Operating, Alarm Condition, Note 1 Operating, Alarm Condition, Note 1 Low Battery or Failed Chamber Test, No Alarm Operating, CO Interconnect Alarm Condition, Note 1 Operating, CO Interconnect Alarm Condition, Note 1 From Start of Local Alarm to IO Active No local alarm, 2 valid pulses required for CO IO=low At Conclusion of Local Alarm or Test No Local Alarm, From IO Active to Alarm No Alarm Condition
Min
9.4 9.4 39 .45 9.6 9.6 1.8 .9 .9 7.2 300 94 450 9.4 90 450 1.35 39 90 4.59
Limits Typ Max
10.5 10.5 43 .5 10.75 10.75 2 1 1 8 336 104 500 10.5 100 500 1.5 43 100 5.1 0 11.5 11.5 47 .55 11.8 11.8 2.2 1.1 1.1 8.9 370 115 550 11.5 110 550 1.65 47 110 5.61
Units
mS mS S S S S S S S S S mS uS mS mS mS mS S S mS S S
LED IS NOT ON
STROBE and IRED Pulse Period
TPER1 TPER1A TPER1B TPER2 TPER3 TPER4
IRED On Time Horn On Time
TON2 THON1 THON2 THON3
Horn Off Time
THOF1 THOF2 THOF3 THOF4 THOF5
IO Delay IO Pulse on Time for CO Alarm IO Pulse Off Time for CO Alarm IO Charge Dump Duration Remote Alarm Delay Timer Period
TIODLY1 TIOPW1 TIOTO1 TIODMP TIODLY2 TTPER
46.2
590 3.7
mS S S S Min
1.2 1.05 8
1.35 1.5 10
1.5 2.0 12
Note 1 - See timing diagram for smoke alarm Horn Temporal Pattern 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.
(c) 2009 Microchip Technology Inc.
DS22176A-page 4
RE46C146
CMOS Photoelectric Smoke Detector ASIC with Intelligent IO and Timer Mode Product Specification R&E International
A Subsidiary of Microchip Technology Inc.
(c) 2009 Microchip Technology Inc.
DS22176A-page 5
RE46C146
CMOS Photoelectric Smoke Detector ASIC with Intelligent IO and Timer Mode Product Specification R&E International
A Subsidiary of Microchip Technology Inc.
Functional Block Diagram
Figure 1
(c) 2009 Microchip Technology Inc.
DS22176A-page 6
RE46C146
CMOS Photoelectric Smoke Detector ASIC with Intelligent IO and Timer Mode Product Specification R&E International
A Subsidiary of Microchip Technology Inc.
PIN DESCRIPTIONS
PIN#
1
PIN NAME
C1
DESCRIPTION
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. 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. Positive input to the photo amplifier. This input is normally connected to the cathode of an external photo diode operated at zero bias. 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. Connect to the positive supply voltage Provides a regulated pulsed output voltage pre-driver for the infrared emitter. This output usually drives the base of an NPN transistor. This bidirectional pin provides the capability to interconnect many detectors in a single system. This pin has an internal pull-down device. This pin is connected to the metal electrode of a piezoelectric transducer. HS is a complementary output to HB and connects to the ceramic electrode of the piezoelectric transducer. 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. A capacitor connected to this pin with a parallel resistor sets the internal clock low time which is approximately the clock period. A resistor between this pin and pin 12 (COSC) sets the internal clock high time. This also sets the IRED pulse width (100-200uS). Connect to the negative supply voltage. In the timer mode this input pin can be used to set an external smoke comparator reference. This input is used to invoke two test modes and the timer mode. This input has an internal pull-down.
2
C2
3 4 5 6 7 8 9 10 11 12 13 14 15 16
DETECT STROBE VDD IRED IO HB HS FEED LED COSC ROSC VSS VSEN TEST
(c) 2009 Microchip Technology Inc.
DS22176A-page 7
RE46C146
CMOS Photoelectric Smoke Detector ASIC with Intelligent IO and Timer Mode Product Specification R&E International
A Subsidiary of Microchip Technology Inc.
Typical Application
Figure 2
Notes: 1) C3 is typical for an alkaline battery. This capacitance should be increased to 4.7uF or greater for a carbon battery. Place C3 as close as possible to the device power pins.
(c) 2009 Microchip Technology Inc.
DS22176A-page 8
RE46C146
CMOS Photoelectric Smoke Detector ASIC with Intelligent IO 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 during local alarm 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 1.3 seconds 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. In a remote alarm the intelligent interconnect circuitry will identify a DC smoke alarm signal and sound the smoke alarm temporal horn pattern. If the IO input is pulsed high twice with a nominal pulse on time greater than 40mS and within 3.7 seconds, a CO alarm condition is detected and the CO temporal horn pattern will sound. The CO temporal pattern will sound at least two times if a remote CO alarm condition is detected.
(c) 2009 Microchip Technology Inc.
DS22176A-page 9
RE46C146
CMOS Photoelectric Smoke Detector ASIC with Intelligent IO 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 not 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 VSEN FEED COSC HORNB LED
Pin Number 7 15 10 12 8 11
Description The IO pin (7) controls the gain capacitor used for the photo amplifier. If IO is low then normal gain is selected. If IO is high then high gain is selected. In diagnostic mode the output of the photo amplifier is gated to this pin and the pull down device is disabled. 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.
(c) 2009 Microchip Technology Inc.
DS22176A-page 10
RE46C146
CMOS Photoelectric Smoke Detector ASIC with Intelligent IO 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
Low BatteryTest Low BatteryWarning Chirp Low Battery Warning Chirp THON3
Horn
THOF3
Chamber Test and Warning is Offset from Low Battery Test and Warning by 21.5 Seconds
(c) 2009 Microchip Technology Inc.
DS22176A-page 11
RE46C146
CMOS Photoelectric Smoke Detector ASIC with Intelligent IO and Timer Mode Product Specification R&E International
A Subsidiary of Microchip Technology Inc.
Timing Diagrams (continued)
Local Alarm Tim ing (not to scale)
TPER2
STROBE
IRED
TPLED2
LED
Sm oke Alarm Horn Tem poral Pattern (not to scale)
No Alarm Local Alarm
THON1 THOF1 THOF2
No Alarm
Horn
TIODLY1
IO
CO Alarm Horn Tem poral Pattern (not to scale)
Remote CO Alarm
THON3 THOF4 THOF5
Horn
TIOPW 1
IO
TIOTO1
Notes: 1. Smoke is not sampled when the horn is active. Horn cycle is self completing in local 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
(c) 2009 Microchip Technology Inc.
DS22176A-page 12
RE46C146
CMOS Photoelectric Smoke Detector ASIC with Intelligent IO and Timer Mode Product Specification
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. (c) 2009, Microchip Technology Incorporated, Printed in the U.S.A., All Rights Reserved. Printed on recycled paper.
R&E International
A Subsidiary of Microchip Technology Inc.
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.
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(R) MCUs and dsPIC(R) DSCs, KEELOQ(R) 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.
(c) 2009 Microchip Technology Inc.
DS22176A-page 13

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