5354

5354 ALLEGRO

Document overview

• Manufacturer or author: Provided By www.digicamel.com(FREE DATASHEET DOWNLOAD SITE)
• PDF pages: 8

Technical content

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 SMOKE DETECTOR WITH INTERCONNECT The A5354CA 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 A5354CA 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 A5348CA. 5354 Always order by complete part number: A5354CA . 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 26110.6

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 n Built-In Hysteresis Reduces False Triggering

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-001-4 Copyright © 1996, Allegro MicroSystems, Inc.

ELECTRICAL CHARACTERISTICS at TA = +25°C, VDD = 9.0 V, VSS = 0 V, C12 = 0.1 µF, R7 = 8.2 MΩ (unless otherwise noted). 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 12 8.0 10 12 ms Low Voltage Threshold 6 T A = 0°C to 50°C 7.2 — 7.8 V Sensitivity Adjust 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 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 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 V15 < V13; No Alarm (No Smoke) Condition as V15 > V13. 5354 SMOKE DETECTOR with INTERCONNECT

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 ELECTRICAL CHARACTERISTICS continued Limits Characteristic Pin Test Conditions Min. Typ. Max. Units Test 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. 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 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 to smoke is set internally 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 VDD . The thresh- old 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. CIRCUIT DESCRIPTION The A5354CA 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 de- tected, 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 hyster- esis 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

TIMING DIAGRAMS IN TYPICAL APPLICATION TYPICAL APPLICATION NO ALARM NO LOW BATTERY STANDBY MODE 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

Dwg. WC-003 ON 12 CLOCK CYCLES 6 CLOCK CYCLES 6 CLOCK CYCLES 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 intercon- nected 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. 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. TO OTHER UNITS NOTE NOTE LOGIC OSC. & TIMING HORN DRIVER V DD Dwg. EC-005-4 V SS 9 V PUSH TO TEST 200 kW 200 kW 200 W 8.2 MW 1 mF 0.1 mF 1 MW 330 kW 0.001 mF 330 W NC NC 5354 SMOKE DETECTOR with INTERCONNECT

Worcester, Massachusetts 01615-0036 (508) 853-5000 I/O OPERATION 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

Dwg. WC-004

(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 5354 SMOKE DETECTOR with INTERCONNECT

Worcester, Massachusetts 01615-0036 (508) 853-5000 SAFETY & SECURITY ICs SELECTION GUIDE Part Number Function A3054KU/SU Multiplexed Two-Wire Hall-Effect Sensor A5347CA Ionization-Type Smoke Detector with Interconnect and Timer 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 A5354CA Ionization-Type Smoke Detector with Interconnect and Reverse-Battery Protection A5355CA Ionization-Type Smoke Detector with Interconnect and Reverse-Battery Protection A5358CA Photoelectric-Type Smoke Detector with Interconnect and Timer 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.