Smoke detector IC allows 10-year battery life
Targeted at the consumer smoke alarm market, the A5303 BiCMOS photoelectric smoke detector circuit with low standby current allows an average 10-year battery life. The device can be used with an infrared optical chamber to sense light scattered from smoke particles.
An internal oscillator and timing circuitry minimize standby power by sensing for smoke for only 100 µs once every 10 s. During this period, the typical chip supply current drawn from the battery is only 2.3 µA. During the 100-µs sample where smoke is being sensed, the supply current reaches a typical value of 210 to 220 µA.
A networking capability allows units to be interconnected so that if any unit senses smoke, all units will sound an alarm. Housed in a 20-pin TSSOP, the chip offers special features to facilitate calibration and testing of the finished detector.
In addition, a 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, and two consecutive cycles of degraded sensitivity are required for a warning signal to occur. ($0.72 ea/1,000 available now.)
Allegro MicroSystems , Worcester , MA
Sales 508-853-5000
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