R&E International A Subsidiary of Microchip Technology Inc. RE46C126 CMOS Ionization Smoke Detector ASIC with Interconnect Product Specification General Description Features The RE46C126 is low power CMOS ionization type smoke detector IC. With few external components this circuit will provide all the required features for an ionization type smoke detector. • • • • • • • • • • An internal oscillator strobes power to the smoke detection circuitry for 10.5mS every 1.66 seconds to keep standby current to a minimum. A check for a low battery condition is performed every 40 seconds when in standby. . A 2/3 duty cycle continuous horn pattern is used for the alarm condition. Guard Outputs for Ion Detector Input +/-0.75pA Detect Input Current Internal Reverse Battery Protection Internal Low Battery Detection Low Quiescent Current Consumption (<6.5uA) Available in 16L PDIP or 16L N SOIC ESD Protection on all Pins Interconnect up to 40 Detectors Compatible with MC14468 Available in Standard Packaging or RoHS Complaint Pb Free Packaging An interconnect pin allows multiple detectors to be connected such that when one unit alarms all units will sound. Although this device was designed for smoke detection utilizing an ionization chamber it can be used in a variety of security applications. Utilizing low power CMOS technology the RE46C126 was designed for use in smoke detectors that comply with Underwriters Laboratory Specification UL217 and UL268. Pin Configuration DETCOMP 1 16 GUARD2 2 15 DETECT LBADJ 3 14 GUARD1 STROBE 4 13 VSEN LED 5 12 OSCAP VDD 6 11 HS RBIAS 7 10 HB FEED 8 9 IO VSS ABSOLUTE MAXIMUM RATINGS PARAMETER Supply Voltage Input Voltage Range Except FEED, IO FEED Input Voltage Range IO Input Voltage Range Reverse Battery Time Input Current except FEED Operating Temperature Storage Temperature Maximum Junction Temperature SYMBOL VDD Vin Vinfd Vio1 TRB Iin TA TSTG TJ VALUE 15 -.3 to Vdd +.3 -10 to +22 -.3 to 17 5 10 -10 to 60 -55 to 125 150 UNITS V V V V S 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. DS22170A-page 1 RE46C126 CMOS Ionization Smoke Detector ASIC Product Specification R&E International A Subsidiary of Microchip Technology Inc. DC Electrical Characteristics at TA = 25°C, VDD=9V, OSCAP=.1uF, RBIAS=8.2MΩ, VSS=0V (unless otherwise noted) Symbol Test Pin Supply Voltage VDD 6 Operating Supply Current IDD1 6 RBIAS=8.2MΩ, OSCAP=.1uF IDD2 6 RBIAS=8.2MΩ, OSCAP=.1uF;Vdd=12V VIH1 8 VIH2 2 VIL1 8 VIL2 2 ILDET1 15 ILDET2 15 ILFD 8 IHDET1 Parameter Input Voltage High Input Voltage Low Input Leakage Low Input Leakage High Test Conditions Min 6 4.5 6.2 No Local Alarm, IO as an Input 6.5 uA 9 uA V V 2.7 V 1 V VDD=9V, DETECT=VSS, 0-40% RH -0.75 pA VDD=9V, DETECT=VSS, 85% RH Note 1 -1.50 pA FEED=-10V -50 uA 15 VDD=9V, DETECT=VDD, 0-40% RH 0.75 pA IHDET2 15 VDD=9V, DETECT=VDD, 85% RH Note 1 1.50 pA IHFD 8 FEED=22V 50 uA IIOL1 2 No Alarm, Vio=Vdd-2V 100 uA No Alarm, Vio=17V 150 uA 1 uA No Local Alarm, IO as an Input 25 2 IIOHZ 4,5 Output Voltage High VOH1 10,11 VOH2 1 VOL1 10,11 VOL2 1,4 VOL3 5 IOL=10mA, VDD=7.2V IIOH1 2 Alarm, Vio=Vdd-2V or Vio=0V -4 IIODMP 2 At Conclusion of Local Alarm or Test, Vio=1V 5 TA=-10 to 60ºC, Note 3 Low Battery Voltage V 4.5 4.5 IIOL2 Output Current Units 12 3 Output Off Leakage High Output Voltage Low Limits Typ Max Output Off IOH=-16mA, VDD=7.2V 6.3 V IOH=-30ua 8.5 V IOL=16mA, VDD=7.2V .9 V IOL=30ua .5 V 3 V -16 mA mA VLB 6 Internal Sensitivity Set Voltage VSET1 13 VSET2 3 Offset Voltage VGOS1 14,15 Guard Amplifier -50 50 mV VGOS2 15,16 Guard Amplifier -50 50 mV VGOS3 13,15 Smoke Comparator -50 50 mV VCM1 14,15 Guard Amplifier, Note 2 2 VDD-.5 V .5 VDD-2 V 170 mV Common Mode Voltage 7.2 7.5 7.8 V 47 50 53 %VDD 65.5 VCM2 13,15 Smoke Comparator, Note 2 Output Impedance ZOUT 14,16 Guard Amplifier Outputs, Note 2 Hysteresis VHYS 13 No Alarm to Alarm Condition %VDD 10 90 130 kΩ Note 1: Sample test only Note 2: Not 100% production tested Note 3: Production test at room with temperature guardbanded limits. © 2009 Microchip Technology Inc. DS22170A-page 2 RE46C126 CMOS Ionization Smoke Detector ASIC with Interconnect Product Specification R&E International A Subsidiary of Microchip Technology Inc. AC Electrical Characteristics at TA = 25°C, VDD=9V, OSCAP=.1uF, RBIAS=8.2MΩ, VSS=0V (unless otherwise noted) Min Limits Typ Max No Alarm Condition 1.34 1.67 2 S Alarm Condition 37.5 41.5 45.8 mS Operating 9.1 10.5 12.9 mS 5 Operating 9.1 10.5 12.9 mS TLOF1 5 Standby, No Alarm 32 40 48 S TLOF2 5 Alarm Condition .9 1 1.1 S THON1 THON2 Symbol Test Pin TPER1 12 TPER2 12 Oscillator Pulse Width TPW 5 LED On Time TLON LED Off Time Parameter Oscillator Period Horn On Time Horn Off Time Test Conditions 10,11 Operating, Alarm Condition, Note 4 141 166 190 mS 10,11 Low Battery, No Alarm 9.4 10.5 12.9 mS THOF1 10,11 Operating, Alarm Condition, Note 4 71 83 95 mS Low Battery, No Alarm 32 40 48 S 1.34 1.67 2.0 S THOF3 10,11 IO Charge Dump Duration TIODMP 2 At Conclusion of Local Alarm or Test IO Delay TIODLY1 2 From Start of Local Alarm to IO Active IO Filter Remote Alarm Delay Units TIOFILT 2 TIODLY2 2 IO pulse width guaranteed to be filtered. IO as Input, No Local Alarm No Local Alarm, IO as input, From IO active to Horn Active 3 .450 S 450 mS 2.2 S Note 4 – See the timing diagram for the horn 2/3 duty cycle pattern. © 2009 Microchip Technology Inc. DS22170A-page 3 RE46C126 CMOS Ionization 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. DS22170A-page 4 RE46C126 CMOS Ionization Smoke Detector ASIC with Interconnect Product Specification R&E International A Subsidiary of Microchip Technology Inc. DEVICE DESCRIPTION and APPLICATION NOTES Note: All timing references are nominal values. Refer to the electrical specifications for limits Internal Timing – With external components as indicated on the application drawing the period of the oscillator is nominally 1.67 seconds in standby. Every 1.66 seconds the detection circuitry is powered up for 10.5mS and the status of the smoke comparator is latched. In addition every 40 seconds the LED driver is turned on for 10.5mS and the status of the low battery comparator is latched. The smoke comparator status is not checked during the low battery test, during the low battery horn warning chirp, or when the horn is on due to an alarm condition. If an alarm condition is detected the oscillator period increases to 41.5mS. Due to the low currents used in the oscillator the capacitor on pin 12 should be a low leakage type. Oscillator accuracy will depend mainly on the tolerance of the RBIAS resistor and OSCAP capacitor. Smoke Detection Circuit – The smoke comparator compares the ionization chamber voltage to a voltage derived from a resistor divider across VDD. This divider voltage is available externally on pin 13 (VSEN). Pin 13 (VSEN) can be used to modify the internal set point for the smoke comparator by using external resistors to VDD or VSS. Nominal values for the internal resistor divider are indicated on the block diagram. These internal resistor values can vary by up to ±20% but the resistor matching will be <2% on any one device. A transmission switch on pin 13 isolates this pin during the low battery test so that the low battery set point will not be affected if external resistors are used to modify the smoke sensitivity set point. The guard amplifier and outputs are always active and will be within 50mV of the DETECT input to reduce surface leakage. The guard outputs also allow for measurement of the DETECT input without loading the ionization chamber. Low Battery Detection - An internal reference is compared to the voltage divided VDD supply. The battery can be checked under load via the LED low side driver output since low battery status is latched at the end of the 11mS LED pulse. Pin 3 (LBADJ) can be used to modify the low battery set point by placing a resistor to VDD or VSS. Note that the internal resistor string is common to both pin 3 and pin 13 so there will be some interaction between the two. Modification of the low battery set point may affect the smoke sensitivity setting. LED Pulse – The LED is pulsed on for 10.5mS every 40S in standby. In alarm the LED is pulsed on for 10.5mS every 1S. For a remote alarm condition the LED is always off. Interconnect – Pin 2 (IO) provides the capability to common many detectors in a single system. If a single unit goes into alarm the IO pin is driven high. This high signal causes the interconnected units to alarm. The LED flashes every 1S for 10.5mS on the signaling unit and is inhibited on the units that are in alarm due to the IO signal. An internal sink device on the IO pin helps to discharge the interconnect line. This dump device is active for 1 clock cycle after the unit exits the alarm condition (1.67S). 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. Testing - By holding pin 12 (OSCAP) low the internal power strobe is active and pin1 (DETCOMP) can be used to check for smoke. Please refer to the timing diagrams. © 2009 Microchip Technology Inc. DS22170A-page 5 RE46C126 CMOS Ionization Smoke Detector ASIC with Interconnect Product Specification R&E International A Subsidiary of Microchip Technology Inc. Typical Application Figure 2 Notes: 1. R3, R4 and C1 are typical values and may be adjusted to maximize sound pressure. 2. C2 should be located as close as possible to the device power pins. 3. Route the pin 8 PC board trace away from pin 7 to avoid coupling. © 2009 Microchip Technology Inc. DS22170A-page 6 RE46C126 CMOS Ionization Smoke Detector ASIC with Interconnect Product Specification R&E International A Subsidiary of Microchip Technology Inc. Timing Diagram Standby Mode; No Low Battery; No Alarm Alarm; No Low Battery Alarm; Low Battery No Alarm; Low Battery Oscillator Pin 15 > Pin 13 1.67S Pin 13 > Pin 15; 130mV Level Shift on Pin 13 Pin 15 > Pin 13 10.5mS Internal Clock 24 Clock Cycles (1S) 24 Clock Cycles (40 S) Floating LED DETCOMP (pin1) Sample Smoke Floating STROBE (pin 4) Low Battery Warning Chirp Horn See Figure Below for Complete Horn Cycle IO (Pin 2) as Output IO Charge Dump TIODMP TIOFILT IO ( Pin 2) as Input LED supressed in remote alarm mode TIODLY2 Horn Start of horn pattern is not synchronized to an external alarm Horn pattern not self completing for external alarm Internal Clock 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 alarm 3. IO Dump active only in local alarm, inactive if external alarm © 2009 Microchip Technology Inc. DS22170A-page 7 RE46C126 CMOS Ionization 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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