CMOS Programmable Ionization Smoke Detector ASIC with
Interconnect, Timer Mode and Alarm Memory
• 6 – 12V Operation
• Low Quiescent Current Consumption
• Programmable Standby Sensitivity
• Programmable HUSH Sensitivity
• Programmable Hysteresis
• Programmable Chamber Voltage for Push-to-Test
(PTT) and Chamber Test
• Programmable ±150 mV Low Battery Set Point
• Internal Ionization Chamber Test
• Internal Low Battery Test
• Internal Power-On Reset and Power-up Low
• Alarm Memory
• Auto Alarm Locate
• Horn Synchronization
• IO Filter and Charge Dump
• Smart Interconnect
• Interconnect up to 40 Detectors
• ±5% All Internal Oscillator
• 9 Minute or 80 Second Timer for Sensitivity
• Temporal or Continuous Horn Pattern
• Guard Outputs for Ion Detector Input
• ±0.75 pA Detect Input Current
• 10-year End-of-Life Indication
The RE46C180 is a next generation low power, CMOS
ionization-type, smoke detector IC. With minimal exter-
nal components, this circuit will provide all the required
features for an ionization-type smoke detector.
An on-chip oscillator strobes power to the smoke
detection circuitry for 5 ms every 10 seconds to keep
the standby current to a minimum.
A check for a Low Battery condition is performed every
80s and an ionization chamber test is performed once
every 320s when in Standby. The temporal horn pattern
complies with the National Fire Protection Association
NFPA 72® National Fire Alarm and Signaling Code® for
emergency evacuation signals.
An interconnect pin allows multiple detectors to be con-
nected, such that when one unit alarms, all units will
sound. A charge dump feature quickly discharges the
interconnect line when exiting a Local Alarm condition.
The interconnect input is also digitally filtered.
An internal 9 minute or 80s timer can be used for a
Reduced Sensitivity mode.
An alarm memory feature allows the user to determine
whether the unit has previously entered a Local Alarm
Utilizing low-power CMOS technology, the RE46C180
is designed for use in smoke detectors that comply with
the Standard for Single and Multiple Station Smoke
Alarms, UL217 and the Standard for Smoke Detectors
for Fire Alarm Systems, UL268.
2011 Microchip Technology Inc.