The RAA239101 is a low-power Analog Front-End (AFE) IC; combined with a microcontroller, photoelectric emitter/detector(s), horn, and minimal external components, it forms a complete smoke detector.

The IC operates from a 3V to 5V or 9V battery and has an LDO to provide power to a microcontroller. The battery-check feature can be used to signal an alarm when the battery is low.

The RAA239101 provides a driver that can switch between two LEDs to pulse the smoke detection LED emitters with a DAC adjustable current. Two photodiode receiver channels with programmable gain amplification using an ADC allow the detection of smoke by sensing the LED light scattered off of smoke in a detection chamber.


  • Ultra-low current consumption
  • 9V or 3V to 5V battery operation
  • LDO for microcontroller supply
  • 10-bit ADC for measuring voltage on 7 analog pins
  • Drives two LED emitters with 8-bit current DAC control from 45mA to 600mA
  • Two photodiode receivers with programmable gain amplifiers
  • General purpose IO
  • Horn driver with clamp diodes
  • SPI interface



  • Photoelectric smoke detectors


Document title Document type Type Date Date
PDF 144 KB Datasheet - Short-form
PDF 1.63 MB Datasheet
PDF 179 KB Product Change Notice
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Design & Development