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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

Supply Voltage [V] 1.7 - 2.0
I2C Bus I2C - 1.8V
Programmable Gain, Integration time, Interrupt
Max. Lux [lux] 20,000
Temperature Range [°C] -30 to 85
Packages 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
Software EVM USB stick content v1_0 (documentation included in installer) English

Technical Documents

Type Description Language
Datasheet Document version 1-03 English
Application Note Optical Window Design (DN13B) English
Application Note Using the Lux Equation (DN29A) English
Application Note Auto-gain Algorithm (DN39) English
Application Note Ambient Light Sensing (DN26) English
Application Note Custom Lux Equation (DN28) English
Application Note Improving Color Sensor Lux Accuracy English
Application Note TSL258x: Accurate ADC Readings after Enable (DN42) English

Environmental Documents

Type Description Language
Material Declaration Form 503020050 - TSL25403M English
Material Declaration Form 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
Other Product Document TSL2540 EvalKit image English

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