Features
- 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
Description
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.
Parameters
| Attributes | Value |
|---|---|
| Function | Photoelectric AFE |
| Automotive Qual. | No |
| Supply Voltage (V) | 9 - 9, 3 - 5 |
| Interface | SPI, GPIO |
| Adj. Analog Gain | 2 - 160 |
| Resolution (bits) | 10 |
| Sample Rate Max (KHz) | 100 |
| Temp. Range (°C) | -40 to +125°C |
Package Options
| Pkg. Type | Pkg. Dimensions (mm) | Lead Count (#) | Pitch (mm) |
|---|---|---|---|
| QFN | 4.0 x 4.0 x 9.00 | 32 | 0.4 |
Application Block Diagrams
 | Household Smoke Detector Ultra-low power smoke detector with integrated AFE for flexible, cost-effective fire safety. |
 | Smoke Detector for Commercial Buildings Commerical smoke detector system for fire alarms achieves ultra-low power consumption with a simple configuration. |
Additional Applications
- Photoelectric smoke detectors