ISL29147

Low Power Ambient Light and Proximity Sensor with Enhanced Infrared Rejection

Product Status: Mass Production

OVERVIEW

The ISL29147 is a low power Ambient Light Sensor (ALS) and proximity (PROX) sensor. It has a built-in IR-LED for the proximity function. The ALS function measures the amount of light (in the visible spectrum) incident on the ISL29147.

The ALS function has a programmable ambient IR-rejection, which allows fine tuning of light source variations and is ideal for light sensor applications under dark protective glass. The ALS provides a 12-bit measurement. A passive optical filter removes unwanted wavelengths (IR or Ultraviolet) to ensure accurate ALS measurement.

The proximity function includes a new offset adjustment to compensate for the IR light reflected off the inside of the protective glass cover and back to the ISL29147 sensor. This offset adjustment allows the sensor to compensate for these internal reflections and preserve the dynamic range of the proximity measurement.

The built-in current-driver pulses an external infrared LED at a programmed current for 90µs. The infrared light that is reflected and received by the ISL29147 is digitized by an 8-bit ADC. The proximity sensor also has a passive optical filter designed to pass IR and reject visible wavelengths.

The ISL29147 provides a hardware pin to indicate an interrupt event. The interrupt pin saves power as the host microcontroller can ‘wake-up’ on an interrupt event and does not need to poll the device for an interrupt event. The interrupt generator is user configurable and provides several options for ALS and PROX trigger configurations. The ISL29147 supports an SMBus compatible I2 C interface for configuration and control.

KEY FEATURES

  • Internal IR-LED and sensor for a complete solution
  • Ideal for applications under dark or tinted glass
  • Enhanced ambient sunlight rejection to 40k Lux
  • Programmable proximity sleep time between proximity measurements optimizes power consumption
  • Hardware interrupt - no polling required
  • Programmable IR compensation to fine-tune ALS performance for various glass compositions
  • Programmable IR LED drive current to 250mA
  • Operates from 2.25V to 3.63V VDD
  • Power-down IDD, typical 0.2µADC
  • Tiny 2.40x4x1.2 (mm) optical co-package

BLOCK DIAGRAM

 Block Diagram

PARAMETRICS

Parameters
ISL29147
Basic Information
Production Status
Mass Production
Peak Spectral Sensitivity
575 nm
VS (min)
2.25 V
VS (max)
3.63 V
ICC
95
Resolution Bits
12
Lux Range (min) (lux)
56.25
Lux Range (max) (lux)
1800
Counts/Lux (max) (Counts)
72.8
Dark ADC Code @ Ev=0Lux (max) (Counts)
1
Gain Selection?
No
Qualification Level
Standard
Bus/Output Interface
I2C
Address Selection Pins?
No
Package Dimensions (mm)
2.40x4x1.2
Features
Enhanced IR Rejection
Enable Pin?
Software Enabled
Temperature Range
-40 to +85

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