I/O A5303 Photoelectric Smoke Detector with Interconnect, Timer, and Latching Alarm Indicator Features and Benefits Description Low average standby current allows 10-year battery life The A5303 is a low-current BiCMOS photoelectric smoke 2.3 to 5.5 V operating range detector circuit with ultra-low standby current and can operate Interconnect option for 10 years powered by inexpensive batteries. This device can Logic outputs to control an external sound IC be used with an infrared optical chamber to sense light scattered Low battery detection and warning from smoke particles. A networking capability allows units to Chamber sensitivity test and warning be interconnected so that if any unit senses smoke all units will Triple horn-chirp to distinguish chamber warning sound an alarm. Special features are incorporated in the design Power-on reset (POR) to facilitate calibration and testing of the finished detector. Digital filter on I/O provides significant noise immunity A variable-gain photoamplifier can be directly interfaced to Timer (hush) mode for enabling reduced sensitivity period an infrared emitter-detector pair. The amplifier gain levels Built-in circuits to reduce false triggering are determined by two external capacitors and are internally ESD protection circuitry on all pins selected depending on the operating mode. Low gain is selected Temporal Horn Pattern, per UL217, NFPA72, ISO8201 during standby and timer modes. During a local alarm, this low Latching alarm indicator identifies alarm-initiating devices gain is increased (internally) by approximately 45% to provide hysteresis. High gain is used during pushbutton test and to Packages: periodically monitor the chamber sensitivity during standby. 20-pin TSSOP The internal oscillator and timing circuitry minimize standby (LE package) power by sensing for smoke for only 100 s once every 10 s. A special three-stage-speedup sensing scheme is incorporated to minimize the time to an audible alarm and also to reduce false triggering. Chamber sensitivity is periodically monitored Not to scale and two consecutive cycles of degraded sensitivity are required for a warning signal to occur. The A5303 is supplied in a thin profile (<1.2 mm overall height) 20-pin TSSOP (LE) package (0.65 mm nominal lead pitch) and a 20-contact QFN (ES) package with exposed thermal 20-contact QFN pad. Both packages are lead (Pb) free with 100% matte tin 4 mm 4 mm 0.75 mm leadframe plating. (ES package) Typical Application Diagram To / from other units 220 V 3 V V DD DD VDD 1.2 V 56 nF V DD C1 10 F Gain LVSET A 3 k 5.6 nF 560 R1 Select Low Batt C2 Low Batt Push-to-test Sample 200 k 5 k TEST R2 A resistor connected DETECT BLINK B A between this pin and VDD or VSS adjusts SOUT0 Smoke the low-battery threshold STROBE Control V - SOUT1 Voice IC outputs DD Chamber Logic 1.6 V SOUT2 B In standby, BLINK = V DD 1 k causes LED to blink, Output to optional V IRED DD BLINK = V causes SS HORN boost converter to LED not to blink drive a piezo horn 100 F ISET LED 3 Red LED HUSH OSCCAP OSC Connect HUSH to Timing 1500 pf VSS to disable timer mode VSS TRES 100 k 10 5303-DS, Rev. 1 Connect to allow timer (hush) mode operationPhotoelectric Smoke Detector A5303 with Interconnect, Timer, and Latching Alarm Indicator Selection Guide Part Number Pb-free and RoHS Package Packing A5303SESTR-T Yes 20-contact QFN 1500 pieces / 7-in. reel A5303SLE-T Yes 20-pin TSSOP (JEDEC MO-153AC) 75 pieces / tube A5303SLETR-T Yes 20-pin TSSOP (JEDEC MO-153AC) 4000 pieces / reel Absolute Maximum Ratings Characteristic Symbol Notes Rating Units Supply Voltage Range V Referenced to V 2.3 to 6 V DD SS DC Input Voltage Range V Referenced to V 0.3 to 6 V IN SS Operating Ambient Temperature Range T Allegro Range S 20 to 85 C A Maximum Junction Temperature T (max) 150 C J Storage Temperature Range T 55 to 150 C stg Thermal Characteristics Characteristic Symbol Test Conditions* Value Units ES Package, 4-layer PCB, based on JEDEC standard 37 C/W Package Thermal Resistance R JA LE Package, estimated, single-layer PCB, minimal exposed copper area 127 C/W *Additional thermal information available on Allegro website. Terminal List Pin-out Diagram Number Name Function ES LE 14 1 SOUT1 Logic push-pull output for controlling an external sound IC 15 2 SOUT0 Logic push-pull output for controlling an external sound IC IRED SOUT0 1 15 16 3 I/O Input-output to interconnected detectors STROBE SOUT1 2 14 17 4 BLINK Logic input for enabling/disabling the LED blink during standby DETECT 3 13 SOUT2 PAD 18 5 HUSH Input for photoamplifier timer mode reference can also disable timer mode C2 4 12 LED C1 5 HORN 19 6 ISET A resistor on this pin connected to VSS sets the IRED output current 11 20 7 VDD Positive supply voltage 1 8 IRED Terminal to drive smoke chamber IR LED 2 9 STROBE Strobed supply (V 2 V) for photoamplifier low-side reference DD 3 10 DETECT Photoamplifier input ES Package 4 11 C2 Sets photoamplifier gain in standby mode SOUT1 20 1 SOUT2 5 12 C1 Sets photoamplifier gain in supervisory mode SOUT0 2 19 LED 6 13 LVSET Optionally used with a resistor to adjust the low-battery threshold I/O 18 3 HORN BLINK 4 17 TEST 7 14 TRES Connection for resistor to set clock times/frequency HUSH 16 5 OSC CAP 8 15 VSS Negative supply voltage ISET 6 15 VSS 9 16 OSC CAP Connection for capacitor and resistor to set clock times/frequency VDD 14 7 TRES IRED 8 13 LVSET 10 17 TEST Enables push-to-test mode starts timer mode, if enabled STROBE 12 9 C1 11 18 HORN Logic output which optionally enables a boost converter to drive a horn DETECT 10 11 C2 12 19 LED Output to drive visible LED LE Package 13 20 SOUT2 Logic push-pull output for controlling an external sound IC PAD Exposed pad for enhanced thermal dissipation Allegro MicroSystems, Inc. 2 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000 www.allegromicro.com 6 20 LVSET VDD TRES 7 19 ISET VSS 8 18 HUSH 9 17 OSC CAP BLINK 10 16 TEST IO