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TSL2740 Ambient Light Sensor

Light-to-Digital Converter with I²C interface


  • Integrated on-chip photopic filter
  • High Sensitivity down to mLux levels
  • 0.18µm process technology with 1.8V I²C
  • 1M:1 dynamic range
  • Programmable proximity offset adjustment
  • Proximity automatic ambient light subtraction


  • Provides near photopic responsiveness
  • Design flexibility for dark glass & placement
  • Reduces power consumption
  • Enables dark room to sunlight operation
  • Compensates for unwanted IR energy system crosstalk reflection
  • Compensates for unwanted ambient light photodiode current

Product parameters

Supply Voltage [V] 1.8V
I²C Bus I²C - 1.8V
Programmable Gain, Integration Time, Interrupt
Integrated Capabilities ALS, Prox
Recommended Operating Distances [cm] 10
Temperature Range [°C] -30 to 85
Packages QFN (10-Pin)

General Description

The TSL2740 includes both proximity detection and very-high sensitivity light-to-digital converter ambient light sensing (ALS) features. The proximity detection feature provides object detection using photodiode detection with reflected IR energy. The detect/release events are interrupt driven, and occur when proximity result crosses upper and/or lower threshold settings. The proximity engine features offset adjustment registers to compensate for unwanted IR energy reflection at the sensor. Proximity results are further improved by automatic ambient light subtraction. The ALS feature approximates the human eye response to light intensity under varying lighting conditions and transforms this light intensity to a digital signal output capable through a 1.8V I²C interface. The ALS sensor features 2 output channels, a visible channel and an IR channel. The visible channel has a photodiode with a photopic Interferometric UV and IR blocking filter and the IR channel has a photodiode with an IR pass filter. Each channel has a dedicated integrating data converter which converts photodiode current into a 16-bit digital output. This digital output can be interfaced with a microprocessor where illuminance in lux is derived to accurately measure ambient light to control a displays baklight.

This product suits for the following applications:

  • Home assistants
  • Smartwatch wearables
  • Display backlight control
  • Tablets
  • Smartphones
  • Medical diagnostics


Name Type Description Language Software TSL2740 EVM USB Stick English

Technical Documents

Name Type Description Version Language
ALSProxDetect_AN000531_1-00.pdf Application Note TSL2771 I2C Communications & Proximity Algorithm (DN30A) 1-00 English
LightSensors_AN000519_1-00.pdf Application Note Colorimetry Tutorial (DN 20) 1-00 English
TSL2740_BD000387_2-00.png Block Diagram TSL2740 Block Diagram 2-00 English
TSL2740_DS000575_1-00.pdf Datasheet Document version 1-00 1-00 English
TSL2740_FS000199_1-00.pdf Factsheet Ambient Light Sensors and Proximity Detection 1-00 English

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