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R&E International
RE46C145
CMOS Photoelectric Smoke Detector ASIC with Interconnect and Timer Mode Product Specification
General Description
The RE46C145 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 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. An internal 10 minute timer can be used for a reduced sensitivity mode. Utilizing low power CMOS technology the RE46C145 was designed for use in smoke detectors that comply with Underwriters Laboratory Specification UL217 and UL268.
Features
* * * * * * * * * * * 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 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
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
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RE46C145
CMOS Photoelectric Smoke Detector ASIC with Interconnect and Timer Mode Product Specification R&E International
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
Symbo l
VDD IDD1 IDD2 IDD3 IDD4
Test Pin
5 5 5 5 5 10 7 15 16 10 7 15 16 1,2,3 10,12 15,16 10 1,2 3,10,12 10 16 15 7 7 11,13 11,13
Test Conditions
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 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
Note 1: Does not include Q3 emitter current.
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RE46C145
CMOS Photoelectric Smoke Detector ASIC with Interconnect and Timer Mode Product Specification R&E International
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 .6
Units
V V V V mA mA
Output Voltage High Output Current
VOh1 IIOH1 IIODMP
5.5 -4 5 6.9 VDD .1 VDD 5.25 2.85 .5 VDD3.7 .01 .3 -50 -30 7.2 7.5 -16
Low Battery Alarm Voltage Output Voltage
VLB VSTOF VSTON VIREDOF VIREDON
V V
VDD 5 3.1
VDD 4.75 .1 3.35 VDD-2 VDD3.3
V V V V V %/C %/C dB dB
Common Mode Voltage Smoke Comparator 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.
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RE46C145
CMOS Photoelectric Smoke Detector ASIC with Interconnect and Timer Mode Product Specification R&E International
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 4,6 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 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 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 Conclusion of Local Alarm or Test 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
Min
9.4 9.4 39 .45 9.6 9.6 1.8 .9 .9 7.2 300 39 94 450 9.5 450 1.35 39 .9
Limits Typ Max
10.5 10.5 43 .5 10.75 10.75 2 1 1 8 336 11.5 11.5 47 .55 11.8 11.8 2.2 1.1 1.1 8.9 370 47 104 500 10.5 500 1.5 43 115 550 11.5 550 1.65 47 1.46 0 600
Units
mS mS S S S S S S S S S mS S uS mS mS mS S S S S mS S Min
LED IS NOT ON
STROBE and IRED Pulse Period
TPER1 TPER1A TPER1B TPER2 TPER3 TPER4 TPER5
IRED On Time Horn On Time
TON2 THON1 THON2
Horn Off Time
THOF1 THOF2 THOF3
IO Charge Dump Duration IO Delay IO Filter
TIODMP TIODLY1 TIOFILT
Remote Alarm Delay Timer Period
TIODLY2 TTPER
1.05 8 10
2.0 12
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.
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RE46C145
CMOS Photoelectric Smoke Detector ASIC with Interconnect and Timer Mode Product Specification R&E International
Functional Block Diagram
Figure 1
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RE46C145
CMOS Photoelectric Smoke Detector ASIC with Interconnect and Timer Mode Product Specification R&E International
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
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RE46C145
CMOS Photoelectric Smoke Detector ASIC with Interconnect and Timer Mode Product Specification R&E International
Typical Application
Figure 2
Notes: The application of the internal 10 minute timer for reduced sensitivity as shown in Figure 2 may be covered by United States patent RE. 33920. 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 4.7uF or greater for a carbon battery. R10, R11 and C6 are typical values and may be adjusted to maximize sound pressure.
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RE46C145
CMOS Photoelectric Smoke Detector ASIC with Interconnect and Timer Mode Product Specification R&E International
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.
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RE46C145
CMOS Photoelectric Smoke Detector ASIC with Interconnect and Timer Mode Product Specification R&E International
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 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 the IO pin (7) 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.
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RE46C145
CMOS Photoelectric Smoke Detector ASIC with Interconnect and Timer Mode Product Specification R&E International
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.
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RE46C145
CMOS Photoelectric Smoke Detector ASIC with Interconnect and Timer Mode Product Specification R&E International
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.
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RE46C145
CMOS Photoelectric Smoke Detector ASIC with Interconnect and Timer Mode Product Specification R&E International
R&E INTERNATIONAL, Inc. reserves the right to make changes without further notice to any products herein to improve reliability, function or design. R&E INTERNATIONAL, Inc. does not assume any liability arising out of the application or use of any product or circuit described herein; neither does it convey any license under its patent rights, nor the rights of others. R&E INTERNATIONAL, Inc. products are not authorized for use as critical components in life support devices or systems without the express written approval of the President of R&E INTERNATIONAL, Inc. Life support devices or systems are devices or systems which are intended for surgical implant into the body to support or sustain life, and whose failure to perform, when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness.
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