Programmable ionization smoke detector ASIC

The RE46C180 is a CMOS programmable ionization smoke detector ASIC with interconnect, timer mode and alarm memory. This device will provide all the required features for an ionization type smoke detector with few external components. An on-chip oscillator strobes power to the smoke detection circuitry for 5ms every 10 seconds to keep standby current to a minimum. A check for a low battery condition is performed every 80 seconds and ionization chamber test is performed once every 320 seconds when in standby. The temporal horn pattern supports the NFPA 72 emergency evacuation signal. An interconnect pin allows multiple detectors to be connected such that when one unit alarms all units will sound. A charge dump feature will quickly discharge the interconnect line when exiting a local alarm. The interconnect input is also digitally filtered. An internal 9 minute or 80s timer can be used for a reduced sensitivity mode. A local alarm memory feature allows the user to determine if the unit has previously entered a local alarm condition. Utilizing low power CMOS technology the RE46C180 is designed for use in smoke detectors that comply with Underwriters Laboratory Specification UL217 and UL268.