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TSL2540 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
  • Automatic AUTO Zero/Dark Count control


  • Provides near photopic responsiveness
  • Design flexibility for dark glass and placement
  • Reduces power consumption
  • Enables dark room to sunlight operation
  • Eliminates system electrical background noise

Product parameters

Interface I²C - 1.8
Supply Voltage [V] 1.7 - 2.0
Programmable Gain, Integration time, Interrupt
Max. Lux [lux] 20000
Temperature Range [°C] -30 to 85
Package QFN (10-Pin)

General description

The TSL2540 is a very-high sensitivity light-to-digital converter that 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 backlight.

This product suits for the following applications:

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


Title Category Headline Buy
Evaluation Kit for TSL2540 Application Board Evaluation Kit for TSL2540


Type Description Language
Application Data EVM documentation v1_0 English

Technical documents

Type Description Language
Datasheet TSL2540 Datasheet Version 2-00 English
Application Note TSL258x: Accurate ADC Readings after Enable (DN42) English
Application Note Optical Window Design (DN13B) English
Application Note Custom Lux Equation (DN28) English
Application Note Ambient Light Sensing (DN26) English
Application Note Auto-gain Algorithm (DN39) English
Application Note Using the Lux Equation (DN29A) English
Application Note Sensitivity to Temperature (DN24) English
Application Note Sensitivity to Wavelength (DN23) English
Application Note Radiometric and Photometric Measurements (DN21) English
Application Note Improving Color Sensor Lux Accuracy English
Application Note Colorimetry Tutorial (DN 20) English
Application Note Basic Pre-Production Light & Color Sensor Solution Validation Process English

Environmental documents

Type Description Language
Material Declaration Form MDF_503020050_TSL25403M English
Material Declaration Form MDF_503020050_TSL25403 English
RoHS Certificate RoHS Certificate TSL2540 English

Other information

Type Description Language
Block Diagram TSL2540 Block Diagram English
Factsheet Light-to-Digital Device Family English
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