Freescale Semiconductor Technical Data MC14467-1 Rev 4, 05/2005 Low-Power CMOS Ionization Smoke Detector IC The MC14467-1, when used with an ionization chamber and a small number of external components, will detect smoke. When smoke is sensed, an alarm is sounded via an external piezoelectric transducer and internal drivers. This circuit is designed to operate in smoke detector systems that comply with UL217 and UL268 specifications. MC14467-1 LOW-POWER CMOS IONIZATION SMOKE DETECTOR IC Features • • • • • • • • • Ionization Type with On-Chip FET Input Comparator Piezoelectric Horn Driver Guard Outputs on Both Sides of Detect Input Input-Production Diodes on the Detect Input Low-Battery Trip Point, Internally Set, can be Altered Via External Resistor Detect Threshold, Internally Set, can be Altered Via External Resistor Pulse Testing for Low Battery Uses LED for Battery Loading Comparator Outputs for Detect and Low Battery Internal Reverse Battery Protection P SUFFIX 16-LEAD PLASTIC DIP CASE 648-08 ORDERING INFORMATION Device Case No. Package MC14467P1 648-08 Plastic Dip Detect Comp. OUT N/C 1 16 Guard Hi-z 2 15 Detect Input Low V Set 3 14 Guard Lo-z Low V Comp. OUT LED 4 13 Sensitivity Set 5 12 Osc Capacitor VDD 6 11 Silver Timing Resistor Feedback 7 10 Brass 8 9 VSS Figure 1. Pin Connections © Freescale Semiconductor, Inc., 2005. All rights reserved. VDD Priezoelectric Horn Driver 8 VDD 4 80 K Low Battery Comp. – 3 11 Latch 10 + 7 VDD 1045 K Oscillator Timer 12 VDD 5 13 + Latch – 15 1125 K 6 9 Led Driver 1 Detect Input 14 Lo-Z VDD + – Active Guard Figure 2. Block Diagram Table 1. Maximum Ratings(1) (Voltages referenced to VSS) Rating Symbol Value Unit DC Supply Voltage VDD −0.5 to + 15 V Input Voltage, All Inputs Except Pin 8 Vin −0.25 to VDD + 0.25 V DC Current Drain per Input Pin, Except Pin 15 = 1 mA I 10 mA DC Current Drain per Output Pin I 30 mA Operating Temperature Range TA −10 to +60 °C Storage Temperature Range Tstg −55 to + 125 °C Reverse Battery Time tRB 5.0 s 1. Maximum Ratings are those values beyond which damage to the device may occur. This device contains circuitry to protect the inputs against damage due to high static voltages or electric fields; however, it is advised that normal precautions be taken to avoid application of any voltage higher than maximum rated voltages to this high impedance circuit. For proper operation it is recommended that except for pin 8, Vin and Vout be constrained to the range VSS ≤ (Vin or Vout ) VDD. For pin 8, refer to the Electrical Characteristics. MC14467-1 2 Sensors Freescale Semiconductor Table 2. Recommended Operating Conditions (Voltages referenced to VSS) Parameter Supply Voltage Symbol Value Unit VDD 9.0 V Timing Capacitor — 0.1 µF Timing Resistor — 8.2 MΩ Battery Load (Resistor or LED) — 10 mA Table 3. Electrical Characteristics (Voltages referenced to VSS, TA = 25°C) Symbol VDD VDC Min Typ(1) Max Unit Operating Voltage VDD — 6.0 — 12 V Output Voltage Piezoelectric Horn Drivers (IOH = -16 mA) Comparators (IOH = -30 µA) Piezoelectric Horn Drivers (IOL = +16 mA) Comparators (IOL = +30 µA) VOH 7.2 9.0 7.2 9.0 6.3 8.5 — — — 8.8 — 0.1 — — 0.9 0.5 Output Voltage - LED Driver, IOL = 10 mA VOL 7.2 — — 3.0 Output Impedance, Active Guard Pin 14 Pin 16 Lo-Z Hi-Z 9.0 9.0 — — — — 10 1000 Operating Current (Rbias = 8.2 MΩ) IDD 9.0 12.0 — — 5.0 — 9.0 12.0 µA Input Current - Detect (40% R.H.) Iin 9.0 — — ±1.0 pA Vlow Vset 9.0 — 7.2 47 — 50 7.8 53 V %VDD Hysteresis vhys 9.0 75 100 150 mV Offset Voltage (measured at Vin = VDD/2 Active Guard Detect Comparator VOS 9.0 9.0 — — — — ±100 ±50 Input Voltage Range, Pin 8 Vin — VSS - 10 — VDD + 10 V Input Capacitance Cin — — 5.0 — pF Common Mode Voltage Range, Pin 15 Vcm — 0.6 — VDD - 2 V Characteristic Internal Set Voltage Low Battery Sensitivity VOL V V V kΩ mV 1. Data labelled “Typ'' is not to be used for design purposes but is intended as an indication of the IC's potential performance. MC14467-1 Sensors Freescale Semiconductor 3 Table 4. Timing Parameters (C = 0.1 µF, Rbias = 8.2 MΩ, VDD = 9.0 V, TA = 25°C, See Figure 7) Symbol Min Typ(1) Max Units tCI 1.34 32 1.67 40 2.0 48 s ms tr 8.0 10 12 ms On Time Off Time PWon PWoff 120 60 160 80 208 104 ms ms LED Output Between Pulses On Time tLED PWon 32 8.0 40 10 48 12 s ms Horn Output (During Low Battery) On Time Between Pulses ton toff 8.0 32 10 40 12 48 ms s Characteristics Oscillator Period No Smoke Smoke Oscillator Rise Time Horn Output (During Smoke) 1. Data labelled “Typ” is not to be used for design purposes but is intended as an indication of the IC’s potential performance. 100.0 10.0 TA = 25°C VDD = 9.0 VDC TA = 25°C ID , Drain Current (mA) ID , Drain Current (mA) 10.0 VDD = 7.2 VDC 1.0 0.1 0 1 2 3 4 5 6 7 8 9 1.0 VDD = 9.0 VDC or 7.2 VDC 0.1 P-CH Source And N-CH Sink Current 0.01 10 0 VDS, Drain To Source Voltage (VDC) 1 2 3 4 5 6 7 1000.0 TA = 25°C VDD = 9.0 VDC VDD = 9.0 VDC 100.0 ID, Drain Current (mA) ID, Drain Current (mA) 10 1000.0 TA = 25°C VDD = 7.2 VDC 10.0 VDD = 7.2 VDC 10.0 P-CH Source Current 1.0 0 9 Figure 4. Typical Comparator Output I-V Characteristic Figure 3. Typical LED Output I-V Characteristic 100.0 8 VDS, Drain To Source Voltage (VDC) 1 2 3 4 5 6 7 VDS, Drain To Source Voltage (VDC) N-CH Sink Current 8 9 10 1.0 0 1 2 3 4 5 6 7 8 9 10 VDS, Drain To Source Voltage (VDC) Figure 5. Typical P Horn Driver Output I-V Characteristic MC14467-1 4 Sensors Freescale Semiconductor DEVICE OPERATION Timing The internal oscillator of the MC14467-1 operates with a period of 1.67 seconds during no-smoke conditions. Each 1.67 seconds, internal power is applied to the entire IC and a check is made for smoke, except during LED pulse, Low Battery Alarm Chirp, or Horn Modulation (in smoke). Every 24 clock cycles a check is made for low battery by comparing VDD to an internal zener voltage. Since very small currents are used in the oscillator, the oscillator capacitor should be of a low leakage type. Detect Circuitry If smoke is detected, the oscillator period becomes 40 ms and the piezoelectric horn oscillator circuit is enabled. The horn output is modulated 160 ms on, 80 ms off. During the off time, smoke is again checked and will inhibit further horn output if no smoke is sensed. During smoke conditions the low battery alarm is inhibited, but the LED pulses at a 1.0 Hz rate. An active guard is provided on both pins adjacent to the detect input. The voltage at these pins will be within 100 mV of the input signal. This will keep surface leakage currents to a minimum and provide a method of measuring the input voltage without loading the ionization chamber. The active guard op amp is not power strobed and thus gives constant protection from surface leakage currents. Pin 15 (the Detect input) has internal diode protection against static damage. Sensitivity/Low Battery Thresholds Both the sensitivity threshold and the low battery voltage levels are set internally by a common voltage divider (please see Figure 2) connected between VDD and VSS. These voltages can be altered by external resistors connected from pins 3 or 13 to either VDD or VSS. There will be a slight interaction here due to the common voltage divider network. The sensitivity threshold can also be set by adjusting the smoke chamber ionization source. Test Mode Since the internal op amps and comparators are power strobed, adjustments for sensitivity or low battery level could be difficult and/or time-consuming. By forcing Pin 12 to VSS, the power strobing is bypassed and the outputs, Pins 1 and 4, constantly show smoke/no smoke and good battery/low battery, respectively. Pin 1 = VDD for smoke and Pin 4 = VDD for low battery. In this mode and during the 10 ms power strobe, chip current rises to approximately 50 µA. LED Pulse The 9-volt battery level is checked every 40 seconds during the LED pulse. The battery is loaded via a 10 mA pulse for 10 ms. If the LED is not used, it should be replaced with an equivalent resistor such that the battery loading remains at 10 mA. Hysteresis When smoke is detected, the resistor/divider network that sets sensitivity is altered to increase sensitivity. This yields approximately 100 mV of hysteresis and reduces false triggering. 1M 1M Test 1 330 Ω 8.2 MΩ 0.1 µF + 9.0 V MC14467-1 16 2 15 3 14 4 13 5 12 6 11 7 10 8 9 0.1 µF 1.5 MΩ* 0.001* µF 220 kΩ* *NOTE: Component values may change depending on type of piezoelectric horn used. Figure 6. Typical Application as Ionization Smoke Detector MC14467-1 Sensors Freescale Semiconductor 5 Standby No Smoke/ No Low Battery Smoke/no Low Battery Smoke/Low Battery 10 m s 40 m s Oscillator (Pin 12) No Smoke/low Battery 1.67 s Detect Out (Pin 1) Low Battery Out (Pin 4) Hysteresis (Internal) (Pins 13 & 14) Sample (Internal) Smoke Horn (Pins 10 & 11) (Note 1) Battery Test LED (Pin 5) Suppressed Chirp (Note 3) 24 Clock Cycles 24 Clock Cycles (0.96 s) (Note 3) 24 Clock Cycles 6 Clock Cycles (10.0 s) (40 s) Notes: 1. Horn modulation is self-completing. When going from smoke to no smoke, the alarm condition will terminate only when horn is off. 2. Comparators are strobed on once per clock cycle (1.67 s for no smoke, 40 ms for smoke). 3. Low battery comparator information is latched only during LED pulse. 4. ~ 100 mVp–p swing. Figure 7. Timing Diagram MC14467-1 6 Sensors Freescale Semiconductor PACKAGE DIMENSIONS NOTES: 1. DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982. 2. CONTROLLING DIMENSION: INCH. 3. DIMENSION L TO CENTER OF LEADS WHEN FORMED PARALLEL. 4. DIMENSION B DOES NOT INCLUDE MOLD FLASH. 5. ROUNDED CORNERS OPTIONAL. -A16 9 1 8 B F C L S SEATING PLANE -TK H G D M J 16 PL 0.25 (0.010) M T A STYLE 1: PIN 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. M CATHODE CATHODE CATHODE CATHODE CATHODE CATHODE CATHODE CATHODE ANODE ANODE ANODE ANODE ANODE ANODE ANODE ANODE STYLE 2: PIN 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. DIM A B C D F G H J K L M S INCHES MILLIMETERS MIN MAX MIN MAX 0.740 0.770 18.80 19.55 0.250 0.270 6.35 6.85 0.145 0.175 3.69 4.44 0.015 0.021 0.39 0.53 0.040 0.70 1.02 1.77 0.100 BSC 2.54 BSC 0.050 BSC 1.27 BSC 0.008 0.015 0.21 0.38 0.110 0.130 2.80 3.30 0.295 0.305 7.50 7.74 0 10 0 10 0.020 0.040 0.51 1.01 COMMON DRAIN COMMON DRAIN COMMON DRAIN COMMON DRAIN COMMON DRAIN COMMON DRAIN COMMON DRAIN COMMON DRAIN GATE SOURCE GATE SOURCE GATE SOURCE GATE SOURCE CASE 648-08 ISSUE R 16-LEAD PLASTIC DIP MC14467-1 Sensors Freescale Semiconductor 7 How to Reach Us: Home Page: www.freescale.com E-mail: [email protected] USA/Europe or Locations Not Listed: Freescale Semiconductor Technical Information Center, CH370 1300 N. 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