MOTOROLA Freescale Semiconductor, Inc. Order this document by MC14468/D SEMICONDUCTOR TECHNICAL DATA MC14468 Low–Power CMOS Ionization Smoke Detector IC with Interconnect 16 1 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. P SUFFIX PLASTIC DIP CASE 648–08 Freescale Semiconductor, Inc... • Ionization Type with On–Chip FET Input Comparator • Piezoelectric Horn Driver ORDERING INFORMATION MC14468P PLASTIC DIP • 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 PIN ASSIGNMENT (16 PIN DIP) • 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 Detect Comp. Out 1 16 Guard Hi–Z I/O 2 15 Detect Input Low V Set 3 14 Guard Lo–Z Strobe Out 4 13 Sensitivity Set LED 5 12 Osc Capacitor VDD 6 11 Silver Timing Resistor 7 10 Brass Feedback 8 9 VSS MAXIMUM RATINGS* (Voltages referenced to VSS) Rating Symbol Value *0.5 to + 15 Unit DC Supply Voltage VDD Input Voltage, All Inputs Except Pin 8 Vin *0.25 to VDD + 0.25 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 Storage Temperature Range Tstg *10 to + 60 *55 to + 125 Reverse Battery Time tRB 5.0 V V °C °C 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 (Vin or Vout) VDD. it is recommended that Vin and Vout be constrained to the range VSS v v REV 3 Motorola Sensor Device Data Motorola, Inc. 2000 For More Information On This Product, Go to: www.freescale.com 1 Freescale Semiconductor, Inc. MC14468 RECOMMENDED OPERATING CONDITIONS (Voltages referenced to VSS) Symbol Value Unit VDD 9.0 V Timing Capacitor — 0.1 µF Timing Resistor — 8.2 MΩ Battery Load (Resistor or LED) — 10 mA Parameter Supply Voltage ELECTRICAL CHARACTERISTICS (TA = 25°C) 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 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 Input Current — Detect (40% R.H.) Iin 9.0 — — Input Current, Pin 8 Iin 9.0 — — Input Current @ 50°C, Pin 15 Iin — — — Internal Set Voltage Low Battery Sensitivity Vlow Vset 9.0 — 7.2 47 Hysteresis vhys 9.0 Offset Voltage (measured at Vin = VDD/2) Active Guard Detect Comparator VOS 9.0 9.0 Freescale Semiconductor, Inc... Characteristic * * VOL V V V kΩ µA "1.0 "0.1 "6.0 µA — 50 7.8 53 V %VDD 75 100 150 mV — — "100 "50 mV — — *10 pA Input Voltage Range, Pin 8 Vin — — VDD + 10 V Input Capacitance Cin — — 5.0 — pF Common Mode Voltage Range, Pin 15 Vcm — 0.6 — I/O Current, Pin 2 Input, VIH = VDD 2 Output, VOH = VDD 2 IIH IOH — — *4.0 25 — — * * VSS pA VDD *2 100 *16 V 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. 2 For More Information On This Product, Go to: www.freescale.com Motorola Sensor Device Data Freescale Semiconductor, Inc. MC14468 TIMING PARAMETERS (C = 0.1 µF, Rbias = 8.2 MΩ, VDD = 9.0 V, TA = 25°C, See Figure 6) Characteristics Oscillator Period Symbol Min Typ# Max Units tCI 1.34 32 1.67 40 2.0 48 s ms No Smoke Smoke Oscillator Rise Time tr 8.0 10 12 ms Horn Output (During Smoke) 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 Freescale Semiconductor, Inc... # Data labelled “Typ’’ is not to be used for design purposes but is intended as an indication of the IC’s potential performance. TO OTHER UNITS VDD VDD I/O FEEDBACK 2 8 45 K – LOW V SET DETECT COMPARATOR OUT 3 11 LOW BATTERY COMPARATOR + SILVER 10 BRASS 1 ALARM LOGIC 280 K 13 DETECT COMPARATOR + POWER–ON RESET – 325 K STROBE OUT 4 15 DETECT INPUT GUARD AMP + LO–Z 14 VDD HI–Z 5 OSC AND TIMING LED 16 – VDD = PIN 6 VSS = PIN 9 12 7 VDD Figure 1. Block Diagram Motorola Sensor Device Data For More Information On This Product, Go to: www.freescale.com 3 Freescale Semiconductor, Inc. MC14468 100.0 10.0 TA = 25°C TA = 25°C ID , DRAIN CURRENT (mA) ID , DRAIN CURRENT (mA) VDD = 9.0 Vdc 10.0 VDD = 7.2 Vdc 1.0 0.1 VDD = 9.0 Vdc or 7.2 Vdc 1.0 0.1 P–CH SOURCE AND N–CH SINK CURRENT 0.01 0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 8 9 10 9 10 Figure 3. Typical Comparator Output I–V Characteristic 1000.0 1000.0 TA = 25°C ID , DRAIN CURRENT (mA) TA = 25°C VDD = 9.0 Vdc 100.0 VDD = 9.0 Vdc 100.0 VDD = 7.2 Vdc 10.0 VDD = 7.2 Vdc 10.0 P–CH SOURCE CURRENT 1.0 0 7 VDS, DRAIN TO SOURCE VOLTAGE (Vdc) Figure 2. Typical LED Output I–V Characteristic ID , DRAIN CURRENT (mA) Freescale Semiconductor, Inc... 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 VDS, DRAIN TO SOURCE VOLTAGE (Vdc) Figure 4. Typical P Horn Driver Output I–V Characteristic 4 For More Information On This Product, Go to: www.freescale.com Motorola Sensor Device Data Freescale Semiconductor, Inc. MC14468 DEVICE OPERATION Freescale Semiconductor, Inc... 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 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 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 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. INTERCONNECT The I/O (Pin 2), in combination with VSS, is used to interconnect 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 voltage. The I/O is disabled for three oscillator cycles after power up, to eliminate false alarming of remote units when the battery 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 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 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 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 16 MC14468 TO OTHER UNITS 330 Ω 0.1 µF + 2 15 3 14 4 13 5 12 6 11 7 10 8 9 0.1 µF 8.2 MΩ 9V *NOTE: Component values may change depending on type of piezoelectric horn used. 1.5 MΩ* 0.001 µF 220 kΩ* Figure 5. Typical Application as Ionization Smoke Detector Motorola Sensor Device Data For More Information On This Product, Go to: www.freescale.com 5 Freescale Semiconductor, Inc. MC14468 Standby No Smoke/ No Low Battery Smoke/Low Battery Smoke/No Low Battery 10 ms No Smoke/Low Battery 1.67 s 40 ms Oscillator (Pin 12) Detect Out (Pin 1) Low Battery (Internal) Hysteresis (Internal) (Pin 13 ) (Pin 14) Sample (Internal) Smoke Low = Disable Freescale Semiconductor, Inc... Horn High = Enable (Pin 10 and 11) (Note 1) Battery Test LED (Pin 5) Suppressed Chirp (Note 3) (Note 3) 24 Clock Cycles 24 Clock Cycles (0.96 s) 24 Clock Cycles 6 Clock Cycles (10.0 s) (40S) Strobe Out (Pin 14) I/O (Pin 2) Output (Local) I/O (Pin 2) Input (Remote) LED Note: Horn Modulation Not Self–Completing (Suppressed LED for Remote Only) Figure 6. Timing Diagram 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. X 6 For More Information On This Product, Go to: www.freescale.com Motorola Sensor Device Data Freescale Semiconductor, Inc. MC14468 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. –A– 16 9 1 8 DIM A B C D F G H J K L M S B F C L S –T– K H Freescale Semiconductor, Inc... SEATING PLANE G D J 16 PL 0.25 (0.010) M T A M CASE 648–08 ISSUE R Motorola Sensor Device Data M STYLE 1: PIN 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. For More Information On This Product, Go to: www.freescale.com INCHES MIN MAX 0.740 0.770 0.250 0.270 0.145 0.175 0.015 0.021 0.040 0.70 0.100 BSC 0.050 BSC 0.008 0.015 0.110 0.130 0.295 0.305 0_ 10 _ 0.020 0.040 CATHODE CATHODE CATHODE CATHODE CATHODE CATHODE CATHODE CATHODE ANODE ANODE ANODE ANODE ANODE ANODE ANODE ANODE MILLIMETERS MIN MAX 18.80 19.55 6.35 6.85 3.69 4.44 0.39 0.53 1.02 1.77 2.54 BSC 1.27 BSC 0.21 0.38 2.80 3.30 7.50 7.74 0_ 10 _ 0.51 1.01 STYLE 2: PIN 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. COMMON DRAIN COMMON DRAIN COMMON DRAIN COMMON DRAIN COMMON DRAIN COMMON DRAIN COMMON DRAIN COMMON DRAIN GATE SOURCE GATE SOURCE GATE SOURCE GATE SOURCE 7 Freescale Semiconductor, Inc... MC14468 Freescale Semiconductor, Inc. Mfax is a trademark of Motorola, Inc. Motorola reserves the right to make changes without further notice to any products herein. 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