5350

5350 ALLEGRO

Document overview

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Technical content

The A5350CA 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 battery-operated safety/security applications. The A5350CA 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.

FEATURES

n Interconnect Up to 125 Detectors n Piezoelectric Horn Driver n Guard Outputs for Detector Input n Pulse Testing for Low Battery n Power-ON Reset n Internal Reverse Battery Protection 5350 Always order by complete part number: A5350CA . ABSOLUTE MAXIMUM RATINGS (Voltages are referenced to VSS ) Supply Voltage Range, Input Voltage Range, Operating Temperature Range, Storage Temperature Range, CAUTION: CMOS devices have input static protection but are susceptible to damage when exposed to extremely high static electrical charges. Data Sheet 26110.5* LOGIC OSC. & TIMING HORN DRIVER GUARD DETECT. IN GUARD SENSITIVITY SET OSC. CAP. HORN HORN – SUPPLY NO CONNECT. I / O LOW-V SET NO CONNECT. LED + SUPPLY TIMING RES. FEEDBACK V DD Dwg. PC-004-1 V SS NC NC

115 Northeast Cutoff, Box 15036

Worcester, Massachusetts 01615-0036 (508) 853-5000 FUNCTIONAL BLOCK DIAGRAM AND TYPICAL APPLICATION 9 V LOW-V SET – SUPPLY + SUPPLY I / O TIMING RES. FEEDBACK DETECT. IN OSC. CAP. NO CONNECTION POWER-ON RESET OSCILLATOR & TIMING LOGIC SENSITIVITY SET GUARD GUARD HORN 1 HORN 2 LED NO CONNECTION V DD 14 15 16 V DD V SS Dwg. FC-001-3 W Copyright © 1995, 1999, Allegro MicroSystems, Inc.

ELECTRICAL CHARACTERISTICS at T A = +25°C, VDD = 9.0 V, VSS = 0 V, C12 = 0.1 µF, R 7 = 8.2 MΩ (unless otherwise noted). 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 V15 < V13. Test Limits Characteristic Pin Test Conditions Min. Typ. Max. Units Supply Voltage Range 6 Operating 6.0 9.0 12 V Detector Input Current 15 0 to 40% RH, V IN = 0 to 9.0 V — — ±1.0 pA Input Offset Voltage 14-15 Active Guard — — ±100 mV 16-15 Active Guard — — ±100 mV 15-13 Detect Comparator — — ±50 mV Common Mode Range 14-15 Guard Amplifier 2.0 — V DD - 0.5 V 13-15 Smoke Comparator 0.5 — V DD - 2.0 V Active Guard Impedance 14 to V SS —1 0— k Ω 16 to V SS — 500 — k Ω Oscillator Period 12 No Alarm 1.34 1.67 2.00 s Alarm 32 40 48 ms Oscillator Pulse Width 12 8.0 10 12 ms Low Voltage Threshold 6 T A = 0 to 50°C 7.2 — 7.8 V Horn Output Voltage 10-11 I OUT = 16 mA, VDD = 9.0 V — 0.1 0.5 V IOUT = 16 mA, VDD = 7.2 V — — 0.9 V IOUT = -16 mA, VDD = 9.0 V 8.5 8.8 — V IOUT = -16 mA, VDD = 7.2 V 6.3 — — V Horn Output ON Time 10-11 Alarm 120 160 208 ms Low Battery 8.0 10 12 ms Horn Output OFF Time 10-11 Alarm 60 80 104 ms Low Battery 32 40 48 s LED Output ON Current 5 V DD = 7.2 V, VOUT = 1.0 V 10 — — mA LED Output ON Time 5 8.0 10 12 ms LED Output OFF Time 5 No Alarm, In Standby 32 40 48 s I/O Current 2 No Alarm, V I/O = VDD - 2.0 V 25 — 60 µA Alarm, VI/O = VDD - 2.0 V -7.5 — — mA I/O Alarm Voltage 2 External “Alarm” In 3.0 — — V I/O Delay 2 “Alarm” Out — 3.0 — s Supply Current 6 V DD = 9.0 V, No Alarm, No Loads — 5.0 9.0 µA VDD = 12 V, No Alarm, No Loads — — 12 µA 5350 SMOKE DETECTOR with INTERCONNECT

Worcester, Massachusetts 01615-0036 (508) 853-5000 The A5350CA 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), the LED is pulsed and a check is made for low battery by comparing V DD to an internal reference. Since very-low currents are used in the device, the oscillator capacitor at pin 12 should be a low-leakage type (PTFE, polystyrene, or polypropylene). Detector Circuitry. 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 ampli- fier is not power strobed and thus provides constant protection from surface leakage currents. The detector input has internal diode protection against static damage. 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 battery alarm is inhibited and the LED is driven at a 1 Hz rate. Sensitivity Adjust. The detector sensitivity must be externally adjusted to the individual characteristics of the ionization chamber by connecting resistors between pin 13 and V DD , and between pin 13 and VSS . Low Battery. The low battery 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 V DD . The threshold can be decreased by connecting a resistor between pin 3 and VSS . The battery voltage level is checked every 40 seconds during the 10 mA, 10 ms LED pulse. If an LED is not used, it should be replaced with an equivalent resistor (typically 500 Ω to 1000 Ω ) such that the battery loading remains at 10 mA. 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 sound their associated horns after a nominal 3 second delay. The LED is suppressed when an alarm is signaled from an interconnected unit. 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 V DD 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. CIRCUIT DESCRIPTION

Dwg. WC-003-1 TYPICAL APPLICATION TIMING DIAGRAMS IN TYPICAL APPLICATION NOTE 1: An external resistor divider is used to adjust sensitivity for the particular smoke chamber. NOTE 2: A resistor to ground or VDD may be added to this pin to modify low battery voltage threshold. Dwg. EC-005-3 TO OTHER UNITS NOTE 1 NOTE LOGIC OSC. & TIMING HORN DRIVER V DD V SS 9 V 200 kW 200 W 8.2 MW 1 mF 0.1 mF 1 MW 200 kW PUSH TO TEST 0.001 mF 330 W NC NC 4.7 MW4.7 MW 200 kW 1.67 s 10 ms 40 ms

24 CLOCK CYCLES

V15 < V13 (NO SMOKE) V15 > V13 (SMOKE) V12 OSC. CAP INTERNAL CLOCK LED SMOKE COMPARATOR SMOKE CHAMBER HORN SAMPLE ALARM NO LOW BATTERY

30 CLOCK CYCLES

ON 12 CLOCK CYCLES 6 CLOCK CYCLES 6 CLOCK CYCLES NO ALARM NO LOW BATTERY STANDBY MODE 5350 SMOKE DETECTOR with INTERCONNECT

Worcester, Massachusetts 01615-0036 (508) 853-5000 Dwg. WC-004 HORN ON OFF HORN NOT SELF COMPLETING WHEN IN REMOTE ONLY ALARM INTERNAL CLOCK HORN V2 IN I/O

4 CYCLES 2 CYCLES

40 ms 1.67 s

72 CLOCK CYCLES

(controlling dimensions) Dimensions in Millimeters (for reference only) NOTES: 1. Lead thickness is measured at seating plane or below. 2. Lead spacing tolerance is non-cumulative. 3. Exact body and lead configuration at vendor’s option within limits shown. 5350 SMOKE DETECTOR with INTERCONNECT 0.014 0.008 0.300 BSC Dwg. MA-001-16A in 0.430 MAX 1 8 0.280 0.240 0.210 MAX 0.070 0.045 0.015 MIN 0.022 0.014 0.100 BSC 0.005 MIN 0.150 0.115 0.775 0.735 0.355 0.204 7.62 BSC Dwg. MA-001-16A mm 10.92 MAX 1 8 7.11 6.10 5.33 MAX 1.77 1.15 0.39 MIN 0.558 0.356 2.54 BSC 0.13 MIN 3.81 2.93 19.68 18.67

Worcester, Massachusetts 01615-0036 (508) 853-5000 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. SAFETY & SECURITY ICs SELECTION GUIDE Part Number Function A3054KU/SU Multiplexed Two-Wire Hall-Effect Sensor A5348CA Ionization-Type Smoke Detector with Interconnect, Timer, and Reverse-Battery Protection A5349CA Ionization-Type Smoke Detector with Interconnect and Timer for AC Line Operation A5350CA Ionization-Type Smoke Detector with Interconnect and Reverse-Battery Protection A5354CA Ionization-Type Smoke Detector with Interconnect and Reverse-Battery Protection A5358CA Photoelectric-Type Smoke Detector with Interconnect and Timer A5364CA Ionization-Type Smoke Detector with Interconnect, Reverse-Battery Protection, and Temporal Horn Pattern A5368CA Ionization-Type Smoke Detector with Interconnect, Timer, Reverse-Battery Protection, and Temporal Horn Pattern