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1Motorola Sensor Device Data Low–Power CMOS ��������� ����� �������� � ���� ����������� The MC14468, 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. • 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 Output for Detect • Internal Reverse Battery Protection • Strobe Output for External Trim Resistors • I/O Pin Allows Up to 40 Units to be Connected for Common Signaling • Power–On Reset Prevents False Alarms on Battery Change MAXIMUM RATINGS* (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 * 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 Vin and Vout be constrained to the range VSS � (Vin or Vout) � VDD. Order this document by MC14468/D ���� � � SEMICONDUCTOR TECHNICAL DATA  Motorola, Inc. 2000 ������� P SUFFIX PLASTIC DIP CASE 648–08 PIN ASSIGNMENT (16 PIN DIP) 16 15 14 13 12 11 10 9 1 2 3 4 5 6 7 8 Detect Comp. Out I/O Low V Set Strobe Out LED VDD Timing Resistor Feedback Guard Hi–Z Detect Input Guard Lo–Z Sensitivity Set Osc Capacitor Silver Brass VSS ORDERING INFORMATION MC14468P PLASTIC DIP 1 16 REV 3 ������� 2 Motorola Sensor Device Data RECOMMENDED OPERATING CONDITIONS (Voltages referenced to VSS) Parameter Symbol Value Unit Supply Voltage VDD 9.0 V Timing Capacitor — 0.1 µF Timing Resistor — 8.2 MΩ Battery Load (Resistor or LED) — 10 mA ELECTRICAL CHARACTERISTICS (TA = 25°C) Characteristic Symbol VDD Vdc Min Typ# 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 VOL 7.2 9.0 7.2 9.0 6.3 8.5 — — — 8.8 — 0.1 — — 0.9 0.5 V V Output Voltage — LED Driver, IOL = 10 mA VOL 7.2 — — 3.0 V Output Impedance, Active Guard Pin 14 Pin 16 Lo–Z Hi–Z 9.0 9.0 — — — — 10 1000 kΩ 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 Input Current, Pin 8 Iin 9.0 — — �0.1 µA Input Current @ 50°C, Pin 15 Iin — — — �6.0 pA Internal Set Voltage Low Battery Sensitivity 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 mV 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 I/O Current, Pin 2 Input, VIH = VDD �2 Output, VOH = VDD �2 IIH IOH — — 25 �4.0 — — 100 �16 µA mA # Data labelled “Typ’’ is not to be used for design purposes but is intended as an indication of the IC’s potential performance. ������� 3Motorola Sensor Device Data TIMING PARAMETERS (C = 0.1 µF, Rbias = 8.2 MΩ, VDD = 9.0 V, TA = 25°C, See Figure 6) Characteristics Symbol Min Typ# Max Units Oscillator Period No Smoke Smoke tCI 1.34 32 1.67 40 2.0 48 s ms Oscillator Rise Time tr 8.0 10 12 ms Horn Output On Time (During Smoke) 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 On Time (During Low Battery) Between Pulses ton toff 8.0 32 10 40 12 48 ms s # Data labelled “Typ’’ is not to be used for design purposes but is intended as an indication of the IC’s potential performance. Figure 1. Block Diagram + – VDD LOW BATTERY COMPARATOR POWER–ON RESET + – VDD 45 K 3 280 K 712 13 325 K + – 15 DETECT INPUT 14 LO–Z 16 HI–Z VDD VDD 8 11 10 5 LOW V SET 1DETECT COMPARATOR OUT ALARM LOGIC DETECT COMPARATOR I/O 2 OSC AND TIMING SILVER BRASS GUARD AMP STROBE OUT 4 LED FEEDBACK TO OTHER UNITS VDD = PIN 6 VSS = PIN 9 ������� 4 Motorola Sensor Device Data Figure 2. Typical LED Output I–V Characteristic Figure 3. Typical Comparator Output I–V Characteristic Figure 4. Typical P Horn Driver Output I–V Characteristic 0 1 2 3 4 5 6 7 8 9 10 0.1 1.0 10.0 100.0 TA = 25°C VDS, DRAIN TO SOURCE VOLTAGE (Vdc) VDD = 7.2 Vdc VDD = 9.0 Vdc 0 1 2 3 4 5 6 7 8 9 10 1.0 10.0 100.0 1000.0 DI , D R AI N C U R R EN T (m A) TA = 25°C VDS, DRAIN TO SOURCE VOLTAGE (Vdc) P–CH SOURCE CURRENT VDD = 7.2 Vdc VDD = 9.0 Vdc 0 1 2 3 4 5 6 7 8 9 10 1.0 10.0 100.0 1000.0 DI , D R AI N C U R R EN T (m A) TA = 25°C VDS, DRAIN TO SOURCE VOLTAGE (Vdc) N–CH SINK CURRENT VDD = 7.2 Vdc VDD = 9.0 Vdc 0 1 2 3 4 5 6 7 8 9 10 0.01 0.1 1.0 10.0 DI , D R AI N C U R R EN T (m A) TA = 25°C VDS, DRAIN TO SOURCE VOLTAGE (Vdc) P–CH SOURCE AND N–CH SINK CURRENT VDD = 9.0 Vdc or 7.2 Vdc DI , D R AI N C U R R EN T (m A) ������� 5Motorola Sensor Device Data DEVICE OPERATION TIMING The internal oscillator of the MC14468 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 Bat- tery 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 out- put if no smoke is sensed. During local smoke conditions the low battery alarm is inhibited, but the LED pulses at a 1.0 Hz rate. In remote smoke, the LED is inhibited as well. 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 volt- age without loading the ionization chamber. The active guard op amp is not power strobed and thus gives constant protec- tion from surface leakage currents. Pin 15 (the Detect input) has internal diode protection against static damage. INTERCONNECT The I/O (Pin 2), in combination with VSS, is used to inter- connect up to 40 remote units for common signaling. A Local Smoke condition activates a current limited output driver, thereby signaling Remote Smoke to interconnected units. A small current sink improves noise immunity during non– smoke conditions. Remote units at lower voltages do not draw excessive current from a sending unit at a higher volt- age. The I/O is disabled for three oscillator cycles after power up, to eliminate false alarming of remote units when the bat- tery is changed. 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 1) connected between VDD and VSS. These volt- ages can be altered by external resistors connected from pins 3 or 13 to either VDD or VSS. There will be a slight inter- action 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 output, Pin 1, constantly shows smoke/no smoke. Pin 1 = VDD for smoke. 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 dur- ing 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. Figure 5. Typical Application as Ionization Smoke Detector MC14468 1 16 2 3 4 5 6 7 8 15 14 13 12 11 10 9 330 Ω 8.2 MΩ + 9 V0.1 µF 1.5 MΩ* 0.001 µF 220 kΩ* 0.1 µF 1 M 1 M TEST *NOTE: Component values may change depending on type of piezoelectric horn used. TO OTHER UNITS ������� 6 Motorola Sensor Device Data Figure 6. Timing Diagram Hysteresis (Internal) (Pin 13 ) (Pin 14) Detect Out (Pin 1) Low Battery (Internal) Sample (Internal) Smoke Horn (Pin 10 and 11) LED (Pin 5) Oscillator (Pin 12) Standby Smoke/No Low Battery Smoke/Low Battery No Smoke/ No Low Battery No Smoke/Low Battery 40 ms 10 ms 1.67 s 24 Clock Cycles (0.96 s) 24 Clock Cycles (40S) 24 Clock Cycles 6 Clock Suppressed ChirpBattery Test (Note 3) (Note 3) (Note 1) Cycles (10.0 s) Strobe Out (Pin 14) I/O (Pin 2) Output (Local) I/O (Pin 2) Input (Remote) LED Note: Horn Modulation Not Self–Completing Low = Disable High = Enable (Suppressed LED for Remote Only) 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 mV p–p swing. ������� 7Motorola Sensor Device Data PACKAGE DIMENSIONS CASE 648–08 ISSUE R 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. –A– B F C S H G D J L M 16 PL SEATING 1 8 916 K PLANE–T– MAM0.25 (0.010) T DIM MIN MAX MIN MAX MILLIMETERSINCHES A 0.740 0.770 18.80 19.55 B 0.250 0.270 6.35 6.85 C 0.145 0.175 3.69 4.44 D 0.015 0.021 0.39 0.53 F 0.040 0.70 1.02 1.77 G 0.100 BSC 2.54 BSC H 0.050 BSC 1.27 BSC J 0.008 0.015 0.21 0.38 K 0.110 0.130 2.80 3.30 L 0.295 0.305 7.50 7.74 M 0 10 0 10 S 0.020 0.040 0.51 1.01 ���� STYLE 1: PIN 1. CATHODE 2. CATHODE 3. CATHODE 4. CATHODE 5. CATHODE 6. CATHODE 7. CATHODE 8. CATHODE 9. ANODE 10. ANODE 11. ANODE 12. ANODE 13. ANODE 14. ANODE 15. ANODE 16. ANODE STYLE 2: PIN 1. COMMON DRAIN 2. COMMON DRAIN 3. COMMON DRAIN 4. COMMON DRAIN 5. COMMON DRAIN 6. COMMON DRAIN 7. COMMON DRAIN 8. COMMON DRAIN 9. GATE 10. SOURCE 11. GATE 12. SOURCE 13. GATE 14. SOURCE 15. GATE 16. SOURCE ������� 8 Motorola Sensor Device Data Motorola reserves the right to make changes without further notice to any products herein. Motorola makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does Motorola assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation consequential or incidental damages. “Typical” parameters which may be provided in Motorola data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. 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