A5349CA

5349 AC SMOKE DETECTOR WITH INTERCONNECT AND TIMER The A5349CA is a low-current, CMOS circuit providing all of the required features for an ionization-type smoke detector. A networking capability allows as many as 125 units to be interconnected so that if any unit senses smoke, all units will sound an alarm. In addition, special features are incorporated to facilitate alignment and test of the finished smoke detector. This device is designed to comply with Underwriters Laboratories Specification UL217. The internal oscillator and timing circuitry keeps standby power to a minimum by powering down the device for 1.66 seconds and sensing smoke for only 10 ms. Every 24 on/off cycles, a check is made for low battery condition. By substituting other types of sensors, or a switch for the ionization detector, this very-low power device can be used in numerous other safety or security applications. The A5349CA is supplied in a low-cost, 16-pin dual in-line plastic package. It is rated for continuous operation over the temperature range of 0°C to +50°C. Data Sheet 26110.4 TIMER START I/O LOW-V SET TIMER OUT LED + SUPPLY TIMING RES. FEEDBACK 1 2 3 4 5 6 7 8 V SS V DD LOGIC 16 15 14 13 12 11 10 9 GUARD 2 DETECT. IN GUARD 1 SENSITIVITY SET OSC. CAP. HORN 2 HORN 1 – SUPPLY OSC. & TIMING HORN DRIVER Dwg. PC-004 FEATURES s s s s s s s Interconnect Up to 125 Detectors Piezoelectric Horn Driver Guard Outputs for Detector Input Low Supply Detection Power-ON Reset Internal Timer & Control for Reduced Sensitivity Built-In Hysteresis Reduces False Triggering ABSOLUTE MAXIMUM RATINGS (Voltages are referenced to VSS) Supply Voltage Range, VDD ................................ -0.5 V to +15 V Input Voltage Range, VIN ........................ -0.3 V to V DD + 0.3 V Input Current, IIN ................................ 10 mA Operating Temperature Range, TA ..................................... 0 °C to +50°C Storage Temperature Range, TS ................................ -55°C to +125°C CAUTION: CMOS devices have input static protection but are susceptible to damage when exposed to extremely high static electrical charges. Always order by complete part number: A5349CA . 5349 AC SMOKE DETECTOR with INTERCONNECT and TIMER FUNCTIONAL BLOCK DIAGRAM AND TYPICAL APPLICATION + SUPPLY V DD 6 I/O 2 V DD FEEDBACK 8 11 HORN 2 3 LOW-V SET – + LOGIC 10 HORN 1 5 LED +V SENSITIVITY SET – SUPPLY 9 V SS 14 GUARD 1 +V DETECT. 15 IN 16 GUARD 2 1 TIMER START – + – + 13 POWER-ON RESET TIMING RES. 7 OSCILLATOR & TIMING OSC. CAP. 12 4 TIMER OUT +V Dwg. FC-005A 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 Copyright © 1995, Allegro MicroSystems, Inc. 5349 AC SMOKE DETECTOR with INTERCONNECT and TIMER ELECTRICAL CHARACTERISTICS at TA = +25°C, VDD = 9.0 V, VSS = 0 V, C12 = 0.1 µF, R7 = 8.2 MΩ (unless otherwise noted). Characteristic Supply Voltage Range Detector Input Current Input Offset Voltage Test Pin 6 15 14-15 16-15 15-13 Hysteresis Common Mode Range 13 14-15 13-15 Active Guard Impedance 14 16 Oscillator Period 12 Limits Test Conditions Operating 0 to 40% RH, VIN = 0 to 9.0 V Active Guard Active Guard Detect Comparator No Alarm to Alarm Guard Amplifier Smoke Comparator to V SS to VSS No Alarm Alarm Oscillator Pulse Width Timer Period Low Voltage Threshold Sensitivity Adj. Voltage Horn Output Voltage 4 4 6 13 10-11 After Pin 1 High-to-Low, No Smoke TA = 0 to 50°C V13 / VDD , pin 13 open circuit IOUT = 16 mA, VDD = 9.0 V IOUT = 16 mA, VDD = 7.2 V IOUT = -16 mA, VDD = 9.0 V IOUT = -16 mA, VDD = 7.2 V Horn Output ON Time 10-11 Alarm Low Battery Horn Output OFF Time 10-11 Alarm Low Battery Timer Start Logic Levels 1 VIH VIL Timer Start Input Current Timer Out Output Current 1 4 VIN = 9.0 V VOUT = 0.5 V Min. 6.0 — — — — 90 2.0 0.5 — — 1.34 32 8.0 8.0 7.2 48.5 — — 8.5 6.3 120 8.0 60 32 3.5 — 20 500 Typ. 9.0 — — — — 130 — — 10 500 1.67 40 10 10 — 50 0.1 — 8.8 — 160 10 80 40 — — — — Max. 12 ±1.0 ±100 ±100 ±50 170 VDD - 0.5 VDD - 2.0 — — 2.00 48 12 12 7.8 51.5 0.5 0.9 — — 208 12 104 48 — 1.5 80 — Units V pA mV mV mV mV V V kΩ kΩ s ms ms min V % V V V V ms ms ms s V V µA µA NOTE 1: Negative current is defined as coming out of (sourcing) the specified device pin. NOTE 2: Alarm (Smoke) Condition is defined as V15 < V13; No Alarm (No Smoke) Condition as V 15 > V 13. Continued next page . . . 5349 AC SMOKE DETECTOR with INTERCONNECT and TIMER ELECTRICAL CHARACTERISTICS continued Test Pin 5 5 Limits Test Conditions VDD = 7.2 V, V OUT = 1.0 V Local Alarm Timer Mode, No Alarm LED Output OFF Time 5 No Alarm, In Standby No Alarm, Timer Mode After Pin 1 High-to-Low I/O Current 2 No Alarm, V I/O = VDD – 2.0 V Alarm, VI/O = VDD – 2.0 V I/O Alarm Voltage I/O Delay Supply Current 2 2 6 External “Alarm” In “Alarm” Out VDD = 9.0 V, No Alarm, No Loads VDD = 12 V, No Alarm, No Loads NOTE 1: Negative current is defined as coming out of (sourcing) the specified device pin. NOTE 2: Alarm (Smoke) Condition is defined as V15 < V13; No Alarm (No Smoke) Condition as V 15 > V 13. Characteristic LED Output ON Current LED Output ON Time Min. 10 Typ. — constant OFF Max. — Units mA — — 8.35 constant ON — s — — 25 -7.5 3.0 — — — 1.67 — — — 3.0 5.0 — — 60 — — — 9.0 12 s µA mA V s µA µA CIRCUIT DESCRIPTION The A5349CA is a low-current CMOS circuit providing all of the required features for an ionization-type smoke detector. Oscillator. An internal oscillator operates with a period of 1.67 seconds during no-smoke conditions. Every 1.67 seconds, internal power is applied to the entire circuit and a check is made for smoke. Every 24 clock cycles (40 seconds), a check is made for low supply by comparing VDD to an internal reference. Since very-low currents are used in the device, the oscillator capacitor at pin 12 should be a lowleakage type (PTFE, polystyrene, or polypropylene). Detector Circuitry. When smoke is detected, the resistor divider network that sets the sensitivity (smoke trip point) is altered to increase the sensitivity set voltage (pin 13) by typically 130 mV with no external connections to pins 3 or 13. This provides hysteresis and reduces false triggering. An active guard is provided on both pins adjacent to the detector input (pin 15). The voltage at pins 14 and 16 will be within 100 mV of the input. 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 amplifier is not power strobed and thus provides constant protection from surface leakage currents. The detector input has internal diode protection against static damage. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 5349 AC SMOKE DETECTOR with INTERCONNECT and TIMER Alarm Circuitry. If smoke is detected, the oscillator period changes to 40 ms and the horn is enabled. The horn output is typically 160 ms ON, 80 ms OFF. During the OFF time, smoke is again checked and will inhibit further alarm output if smoke is not sensed. During smoke conditions the low-supply alarm is inhibited. LED. The LED is continuously ON during the standby mode indicating the unit is receiving power. During a remote alarm condition the LED remains ON. The LED is OFF during a local alarm condition. Sensitivity Adjust. The detector sensitivity to smoke is set internally by a voltage divider connected between VDD and VSS. The sensitivity can be externally adjusted to the individual characteristics of the ionization chamber by connecting a resistor between pin 13 and VDD , or between pin 13 and VSS. Low Supply. The low supply threshold is set internally by a voltage divider connected between VDD and VSS. The threshold can be increased by connecting a resistor between pin 3 and VDD . The threshold can be decreased by connecting a resistor between pin 3 and VSS. The supply voltage level is checked every 40 seconds. Timer. An internal timer is provided that can be used in various configurations to allow for a period of reduced smoke detector sensitivity (“hush”). When a high-to-low transition occurs at pin 1, the internal timer is reset, the timer mode enabled, and the circuit reset to a no-alarm condition (the LED will flash at a 10 second rate). If the level of smoke is increased such that the reduced sensitivity level is reached, the device will go into the alarm condition. The timer, however, will continue to completion of the nominal 10-1/4 minute period (368 clock cycles). If the timer mode is not used, pin 1 should be tied low. I/O. A connection is provided at pin 2 to allow multiple smoke detectors to be commoned. If any single unit detects smoke (I/O is driven high), all connected units will TYPICAL APPLICATION 50 kΩ + SUPPLY TIMER MODE 200 kΩ 200 kΩ 1 200 Ω 2 NOTE 3 330 Ω 5 6 8.2 MΩ 7 1 µF 8 V SS V DD 3 4 LOGIC 15 14 13 12 11 10 9 0.1 µF NOTE 1 16 PUSH TO TEST OSC. & TIMING HORN DRIVER 1 MΩ 200 kΩ TO OTHER UNITS 0.001 µF NOTE 2 Dwg. EC-005-1A NOTE 1: Use an external resistor to adjust sensitivity for a particular smoke chamber. NOTE 2: Select resistor to reduce sensitivity during timer mode. NOTE 3: A resistor to ground or V DD may be added to this pin to modify low battery voltage threshold. NOTE 4: Reverse supply protection must be supplied externally. sound their associated horns after a nominal 3 second delay. The LED remains ON when an alarm is signaled from an interconnected unit and a local smoke condition does not exist. Testing. On power up, all internal counters are reset. Internal test circuitry allows for low-battery check by holding pins 8 and 12 low during power up, then reducing VDD and monitoring HORN1 (pin 10). All functional tests can be accelerated by driving pin 12 with a 2 kHz square wave. The 10 ms strobe period must be maintained for proper operation of the comparator circuitry. 5349 AC SMOKE DETECTOR with INTERCONNECT and TIMER TIMING DIAGRAMS IN TYPICAL APPLICATION NON-TIMER MODE NO ALARM NO LOW BATTERY STANDBY MODE V12 OSC. CAP 1.67 s 10 ms 40 ms ALARM NO LOW BATTERY ALARM AND LOW BATTERY NO ALARM LOW BATTERY INTERNAL CLOCK 24 CLOCK CYCLES 24 CLOCK CYCLES 30 CLOCK CYCLES LED LED ON LED OFF 12 CLOCK CYCLES 6 CLOCK CYCLES 6 CLOCK CYCLES SMOKE COMPARATOR SAMPLE LOW BATTERY WARNING HORN ON OFF HORN SMOKE CHAMBER V15 < V13 (SMOKE) V15 > V13 (NO SMOKE) Dwg. WC-006 TIMER MODE V12 OSC. CAP 1.67 s 10 ms INTERNAL CLOCK 368 CLOCK CYCLES TIMER START TIMER OUT 6 CLOCK CYCLES OUTPUTS OFF LED ON OFF ON OFF END OF TIMER NOTIFICATION HORN Dwg. WC-007 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 5349 AC SMOKE DETECTOR with INTERCONNECT and TIMER I/O OPERATION REMOTE ALARM MODE 40 ms 1.67 s INTERNAL CLOCK 4 CYCLES 2 CYCLES HORN HORN ON OFF V2 IN I/O HORN NOT SELF COMPLETING WHEN IN REMOTE ONLY ALARM LOCAL ALARM MODE INTERNAL CLOCK HORN HORN ON OFF 72 CLOCK CYCLES V2 OUT I/O Dwg. WC-004 5349 AC SMOKE DETECTOR with INTERCONNECT and TIMER Dimensions in Inches (controlling dimensions) 16 9 0.014 0.008 0.430 0.280 0.240 MAX 0.300 BSC 1 0.070 0.045 0.100 0.775 0.735 BSC 8 0.005 MIN 0.210 MAX 0.015 MIN 0.150 0.115 0.022 0.014 Dwg. MA-001-16A in Dimensions in Millimeters (for reference only) 16 9 0.355 0.204 10.92 7.11 6.10 MAX 7.62 BSC 1 1.77 1.15 2.54 19.68 18.67 BSC 8 0.13 MIN 5.33 MAX 0.39 MIN 3.81 2.93 0.558 0.356 Dwg. MA-001-16A mm Allegro MicroSystems, Inc. reserves the right to make, from time to time, such departures from the detail specifications as may be required to permit improvements in the design of its products. The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, Inc. assumes no responsibility for its use; nor for any infringements of patents or other rights of third parties which may result from its use. 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000