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TSL2521 - Ambient Light Sensor with Flicker Detection

Hightly sensitive ambient light sensor with selective flicker detection


  • 1mlux detectable illuminance
  • UV/IR blocking filter for clear channel
  • ALS interrupt with thresholds
  • Flicker-immune ALS sensing with programmable integration time
  • Cuncurrent flicker and ALS measurement with new simplified readout methodology
  • Up to 7kHz flicker detection (14kHz sampling)
  • Configurable sleep mode
  • Interrupt-driven device
  • Digital and analog saturation flags


  • Invisible ALS sensing under any glass type
  • Unique fast ALS integration mode
  • Integrated ambient light flicker detection on chip
  • Low power consumption and minimum I²C traffic
  • Integrated status checking for all functions

Product parameters

Supply Voltage [V] 1.7 -1.98
Interface I²C - 1.8V
Programmable Gain, integration time, interrupt, configuration
Max. Lux [lux]
Temperature Range [°C] -30 to 85
Package OLGA, Pin coun 6

General description

The TSL2521 features ambient light sensing, as well as flicker detection. The device comes in a low-profile and small footprint, L2.0mm x W1.0mm x H0.5mm optical QFN package. The Ambient Light Sensing function provides two concurrent ambient light sensing channels, which can be arbitrarily connected to the photodiodes via a programmable multiplexer. TSL2521 incorporates a set of Infrared photodiodes and a set of clear photodiodes. The clear photodiode area is covered with a UV/IR blocking filter. This architecture accurately measures ambient light and enables the calculation of irradiance of different light sources. Calculation results help to improve display appearance and picture taking. The device also integrates direct detection of ambient light flicker. Flicker detection is executed in parallel with ambient light sensing and has independent gain configuration. The flicker detection engine will sample and buffer data for calculating flicker frequencies externally on a host CPU.

This product suits for the following applications:

  • Indoor/outdoor brightness information
  • Brightness management for displays
  • Camera image correction assistance
  • Flicker-immune camera operation
  • Behind OLED ambient light sensing


Title Category Headline Buy
TSL2521 Eval Kit Application Board Evaluation Kit for TSL2521

Technical documents

Type Description Language
Datasheet TSL2521 datasheet English
Application Note Basic Pre-Production Light & Color Sensor Solution Validation Process English
Application Note TSL2521 ALS/Flicker English
Special Datasheet TSL2521 short datasheet English

Other information

Type Description Language
Block Diagram TSL2521 Block Diagram
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