5364

5364 ALLEGRO

Document overview

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Technical content

The A5364CA 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 A5364CA 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. Similar devices. with an internal timer to allow for a period of reduced sensitivity (“hush”), are available as the A5368CA. Always order by complete part number: A5364CA . Data Sheet26110.7A 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. 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 VSS NC NC

FEATURES

I Interconnect Up to 125 Detectors I Piezoelectric Horn Driver I Guard Outputs for Detector Input I Pulse Testing for Low Battery I Power-ON Reset I Internal Reverse Battery Protection I Built-In Hysteresis Reduces False Triggering I Temporal Horn Pattern 5364

115 Northeast Cutoff, Box 15036

Worcester, Massachusetts 01615-0036 (508) 853-5000 FUNCTIONAL BLOCK DIAGRAM AND TYPICAL APPLICATION Copyright © 1998, 1999 Allegro MicroSystems, Inc. 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 HORN1 HORN 2 LED NO CONNECTION VDD 14 15 16 VDD VSS Dwg. FC-001-4

www.allegromicro.com 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 Hysteresis 13 No Alarm to Alarm 90 130 170 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 4 8.0 10 12 ms Low Voltage Threshold 6 T A = 0 to 50°C 7.2 — 7.8 V Sensitivity Adj. Voltage 13 V 13/VDD, pin 13 open circuit 48.5 50 51.5 % 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 (see figure, time “A”) 450 500 550 ms Low Battery 8.0 10 12 ms Horn Output OFF Time 10-11 Alarm (see figure, time “B”) 450 500 550 ms Alarm (see figure, time “C”) 1350 1500 1650 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 No Local Alarm; Not Latched 8.0 10 12 ms LED Output OFF Time 5 No Alarm, In Standby 32 40 48 s ELECTRICAL CHARACTERISTICS at TA = +25°C, VDD = 9.0 V, VSS = 0 V, C12 = 0.1 µF, R7 = 8.2 MΩ (unless otherwise noted). Continued next page . . .NOTE 1: Negative current is defined as coming out of (sourcing) the specified device pin. NOTE 2: Alarm (Smoke) Condition is defined as V 15 < V13; No Alarm (No Smoke) Condition as V 15 > V13.

Worcester, Massachusetts 01615-0036 (508) 853-5000 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 Test Limits Characteristic Pin Test Conditions Min. Typ. Max. Units ELECTRICAL CHARACTERISTICS (continued) CIRCUIT DESCRIPTION The A5364CA 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. Because very-low currents are used in the device, the oscillator capacitor at pin 12 should be a low-leakage type (PTFE, polysty- rene, 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 connec- tions 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. Alarm Circuitry. If smoke is detected, the oscillator period changes to 40 ms and the horn is enabled. The horn output is typically 0.5 s horn pattern). During the OFF time, smoke is 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 to smoke is set inter- nally by a voltage divider connected between V DD and VSS. The sensitivity can be externally adjusted to the individual characteristics of the ionization chamber by connecting a resistor between pin 13 and V DD, or 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 in- creased by connecting a resistor between pin 3 and V DD. The threshold can be decreased by connecting a resistor between pin 3 and V SS. 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. NOTE 1: Negative current is defined as coming out of (sourcing) the specified device pin. NOTE 2: Alarm (Smoke) Condition is defined as V 15 < V13; No Alarm (No Smoke) Condition as V 15 > V13.

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19 CLOCK CYCLES

1.67 s NO ALARM NO LOW BATTERY STANDBY MODE 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

"A" ALARM AND LOW BATTERY NO ALARM LOW BATTERY Dwg. WC-003-3

12 CLOCK

"B"

13 CLOCK

73 CLOCK CYCLESI/O

"C" 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 opera- tion of the comparator circuitry. TYPICAL APPLICATION TO OTHER UNITS NOTE NOTE LOGIC OSC. & TIMING HORN DRIVER V DD Dwg. EC-005-4 VSS 9 V PUSH TO TEST 200 kΩ 200 kΩ 200 Ω 8.2 MΩ 1 µF 0.1 µF 1 MΩ 330 kΩ 0.001 µF 330 Ω NC NC NOTE 1: Use an external resistor to adjust sensitivity for a particular smoke chamber. NOTE 2: A resistor to ground or V DD may be added to this pin to modify low battery voltage threshold. TIMING DIAGRAM IN TYPICAL APPLICATION

Worcester, Massachusetts 01615-0036 (508) 853-5000 I/O OPERATION INTERNAL CLOCK HORN V2 IN I/O 1.67 s40 ms

72 CLOCK CYCLES

Dwg. WC-004-2 HORN HORN CYCLE NOT SELF COMPLETING AFTER REMOTE OR LOCAL ALARM CONDITION IS REMOVED SINGLE HORN PULSE IN PROGRESS IS SELF COMPLETING AFTER LOCAL ALARM CONDITION IS REMOVED SHADED AND UNSHADED AREAS ARE DIFFERENT TIME SCALES

www.allegromicro.com Dimensions in Inches (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. 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 The products described here are manufactured under one or more 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 performance, reliability, or manufacturability of its products. Before placing an order, the user is cautioned to verify that the information being relied upon is current. Allegro products are not authorized for use as critical components in life-support devices or systems without express written approval. The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, Inc. assumes no responsi- bility for its use; nor for any infringement of patents or other rights of third parties which may result from its use. SAFETY & SECURITY ICs 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