R&E International A Subsidiary of Microchip Technology Inc. RE46C143 CMOS Photoelectric Smoke Detector ASIC with Interconnect Product Specification General Description Features The RE46C143 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 8.1 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 75% Duty Cycle Horn Pattern Low Battery and Chamber Test Compatible with Motorola MC145010 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 40 seconds when in standby. The alarm horn pattern utilizes a 75% duty cycle. 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 LBSET 3 14 VSS STROBE 4 13 ROSC VDD 5 12 COSC IRED 6 11 LED IO 7 10 FEED HORNB 8 9 DETECT Utilizing low power CMOS technology the RE46C143 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 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 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. DS22178A-page 1 RE46C143 CMOS Photoelectric Smoke Detector ASIC with Interconnect 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 6 10 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, Note 1 FEED VIH2 7 No Local Alarm, IO as an Input 3.2 V VIH4 16 TEST 8.5 V VIL1 10 FEED VIL2 7 No Local Alarm, IO as an Input VIL4 16 IIL1 1,2,3 IIL2 12,15 TEST VDD=12V, COSC=12V, STROBE active VDD=12V, Vin=VSS IIL3 16 ILFD 10 IIH1 1,2 IIH2 3,12,15 IHFD 10 FEED=22V 50 uA IPD1 16 Vin=VDD .25 10 uA IPDIO1 7 Vin=VDD 20 80 uA IPDIO2 7 Vin=17V, VDD=12 140 uA IOZL1 11,13 Output Off, Output=VSS -1 uA IOZH1 11,13 Output Off, Output=VDD 1 uA 6.2 Units 12 V 4 6 uA 5.5 8 uA 2 mA 3 mA 4.5 4.5 V 2.7 V 1.5 V 7 V -100 nA -100 nA VDD=12V, Vin=VSS -1 uA FEED=-10V VDD=12V, Vin=VDD, STROBE active VDD=12V, Vin=VDD -50 uA 100 nA 100 nA Note 1: Does not include Q3 emitter current. © 2009 Microchip Technology Inc. DS22178A-page 2 RE46C143 CMOS Photoelectric Smoke Detector ASIC with Interconnect 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 Ioh=-16mA, VDD=6.5V 5.5 Output Current IIOH1 7 -4 IIODMP 7 VLB 5 VSTOF 4 VSTON 4 VIREDOF 6 VIREDON 6 VCM1 1,2,3 Alarm, Vio=Vdd-2V or Vio=0V At Conclusion of Local Alarm or Test, Vio=1V R14=100K, R15=47K, ILed=10mA 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 Vref - TCST 4 TCIRED 6 ΔVSTON ΔVIREDON Low Battery Alarm Voltage Output Voltage Common Mode Voltage Smoke Compare Reference Temperature Coefficient Line Regulation Internal Reference 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 Limits Typ Max V V -16 5 2.25 V V .6 6.9 VDD .1 VDD 5.3 Units mA mA 7.2 7.5 V V VDD 5 3.1 VDD 4.7 .1 V V 3.75 V .5 VDD-2 V VDD3.85 VDD3.15 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. DS22178A-page 3 RE46C143 CMOS Photoelectric Smoke Detector ASIC with Interconnect 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 Test Conditions Min Limits Typ Max No Alarm Condition, Note 2 9.4 10.5 11.5 mS Units TON1 11,4 Operating 9.4 10.5 11.5 mS TPLED1 11 Standby, No Alarm 38 43 47 S TPLED2 11 Local Alarm Condition .6 .67 .74 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 Horn On Time THON1 8,9 THON2 8,9 THOF1 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 Pushbutton Test Chamber Test or Low Battery Test, no Alarms Operating, Note 2 Operating, Alarm Condition, Note 1 Low Battery or Failed Chamber Test , No Alarm 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 LED IS NOT ON S 9.7 10.5 11.8 S 2.42 2.7 2.96 S 1.21 1.33 1.47 S 1.21 1.33 1.47 S 9.7 10.5 11.8 S 336 39 mS 47 S 94 104 115 uS 227 252 277 mS 9.5 10.5 11.5 mS 76 84 92 mS 39 43 47 S 1.46 S .91 0 .75 S 600 mS 1.65 S Note 1 – See timing diagram for Horn Temporal Pattern Note 2 - 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. DS22178A-page 4 RE46C143 CMOS Photoelectric Smoke Detector ASIC with Interconnect Product Specification R&E International A Subsidiary of Microchip Technology Inc. Functional Block Diagram Figure 1 © 2009 Microchip Technology Inc. DS22178A-page 5 RE46C143 CMOS Photoelectric Smoke Detector ASIC with Interconnect 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 a 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 LBSET 16 TEST © 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. This input is connected to a VDD reference voltage to set the low battery warning voltage. This input is used to invoke two test modes. This input has an internal pull-down. DS22178A-page 6 RE46C143 CMOS Photoelectric Smoke Detector ASIC with Interconnect 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. DS22178A-page 7 RE46C143 CMOS Photoelectric Smoke Detector ASIC with Interconnect 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 40 seconds. In a local alarm condition or the push to test alarm the LED pulse frequency is increased to once every 0.5 seconds. In the case of a remote alarm the LED not active. 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 500mS 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. DS22178A-page 8 RE46C143 CMOS Photoelectric Smoke Detector ASIC with Interconnect 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 40 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 40 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. The low battery alarm threshold is approximately equal to ((5*R15)/R14)+5 where R15 and R16 are in the same units. 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 10mS nominal. Pin Name IO Pin Number 7 LBSET 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 LBSET (15). Amplification occurs during the IRED active time. If IO is high then this pin controls the gain capacitor that is used. If LBSET is low then normal gain is selected and the photo amp output appears on C1 (1). If LBSET is high then high gain is selected and the photo amp output is on C2 (2). If LBSET (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. DS22178A-page 9 RE46C143 CMOS Photoelectric Smoke Detector ASIC with Interconnect 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. DS22178A-page 10 RE46C143 CMOS Photoelectric Smoke Detector ASIC with Interconnect 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 Horn Timing No Alarm Local or Remote Alarm THON1 No Alarm THOF1 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. 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. DS22178A-page 11 RE46C143 CMOS Photoelectric Smoke Detector ASIC with Interconnect 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. 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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. DS22178A-page 12