A5303SESTR-T

• Product introduction

The A5303 is a low current BiCMOS with ultra-low standby currentPhotoelectric smoke detector, can be powered by an inexpensive battery and runs for up to 10 years. The device can be used with an infrared chamber to sense light emitted by smoke particles. Networking allows devices to be interconnected, and when any device detects smoke, all devices can sound an audible alarm. Special features are also integrated into the design to facilitate interoperability and testing of the finished detector.

The variable gain optical amplifier allows direct interaction with the IR emitter-detector pair. The amplifier gain level is determined by two external capacitors and selected internally based on the operating mode. Select low gain in standby and timer modes. When a local alarm occurs, this low gain increases (internally) by about 45% to provide hysteresis. High gain is used when periodically monitoring optical chamber sensitivity in key test or standby mode. Built-in oscillator and timing circuitry ensure that only 100 μs of smoke is detected every 10 s, significantly reducing standby power consumption. In addition, a special third-order acceleration sensing scheme is integrated to reduce the time to sound an audible alarm while reducing false triggering. The sensitivity of the optical chamber is monitored periodically, and a warning signal is issued when two consecutive periods of sensitivity degradation occur.

The A5303 features an ultra-thin (

• Ultra-low average standby current enables up to 10 years of battery life
• 2.3 to 5.5 V operating voltage range
• Interconnect options
• The logic output controls the external sound IC
• Low battery detection and warning
• Light chamber sensitivity test with warning
• Triple horn chip discriminating light chamber warning
• Power-On Reset (POR)
• Digital filters at the input/output provide excellent noise immunity
• Timer (silent) mode is used to initiate periods of reduced sensitivity
• Built-in circuitry reduces false triggering
• ESD protection circuitry is provided for all pins
• Instantaneous horn mode to UL217, NFPA72 and ISO8201 standards
• The latch alarm indicator identifies the device that triggered the alarm