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TSL235 Light-to-Frequency

Converter sidelooker package


  • 1M:1 input dynamic range
  • Low dark frequency (0.4Hz typical)
  • High irradiance responsivity 0.6kHz/(µW/cm2) @ λp = 635nm
  • 2X gain lense


  • Detects light intensity at a high resolution
  • Provides low light level operation
  • Provides for high sensitivity to detect a small change in light
  • Provides additional sensitivity advantages

Product parameters

Supply Voltage [V] 2.7-5.5
Responsivity [Hz/µW/cm²] 625 @ 635
Max. Output Frequency [MHz] 0.5
Selectable Sensitivity and Full-Scale Output Frequency
Output Frequency Tolerances [+/- %] 20
Temperature Range [°C] -25 to 70
Packages S
Remark Not recommended for new design. Please see Ambient Light Sensors device family.

General Description

The TSL235R light-to-frequency converter combines a silicon photodiode and a current-to-frequency converter on a single monolithic CMOS integrated circuit. Output is a square wave (50% duty cycle) with frequency directly proportional to light intensity (irradiance) on the photodiode. The digital output allows direct interface to a microcontroller or other logic circuitry. The device has been temperature compensated for the ultraviolet-to-visible light range of 320 nm to 700 nm and responds over the light range of 320 nm to 1050 nm. The TSL235R is characterized for operation over the temperature range of −25°C to 70°C and is supplied in a 3-lead clear plastic sidelooker package with an integral lens. When supplied in the lead (Pb) free package, the device is RoHS compliant.

This product suits for the following applications:

  • Pulse oximetry
  • Color sensing
  • Turbidity sensing
  • Optical switch


Title Category Headline Buy
Light-to-FrequencyEvalKit Application Board Evaluation Kit for Light-to-Frequency Sensors

Technical Documents

Name Type Description Version Language
LightSensors_AN000519_1-00.pdf Application Note Colorimetry Tutorial (DN 20) 1-00 English
TSL235R_BD000185_1-00.png Block Diagram TSL235R Block Diagram 1-00 English
TSL235R_DS000120_3-00.pdf Datasheet Document Version 1-01 3-00 English
TSL235R_TSL237_TSL237T_TSL238T_PD000365_1-00.png Other Product Document Light-to-FrequencyEvalKit Image 1-00 English
TSL235R_RC000115_1-00.pdf RoHS Certificate RoHS Certificate TSL235R 1-00 English
TSL235R_RC000117_1-00.pdf RoHS Certificate RoHS Certificate TSL235R 1-00 English
TSL235R_RC000122_1-00.pdf RoHS Certificate RoHS Certificate TSL235R 1-00 English

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