Asset Publisher

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
Package 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.

Not Recommended for New Designs!

ams-OSRAM AG is discontinuing production of this device. Final lifetime buy order must be placed by OCTOBER 15, 2021. Please contact your local sales representative for further information regarding available or planned replacement options.

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

Type Description Language
Datasheet Document Version 1-01 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
RoHS Certificate RoHS Certificate TSL235R English
RoHS Certificate RoHS Certificate TSL235R English
RoHS Certificate RoHS Certificate TSL235R English


Type Description Language
EoL Notification TSL1x_TSL2xx_TSL25xx_TSL4531 (issued 2017-Feb) English
EoL Notification Plano Test Site (issued May-20-2021) English

Other information

Type Description Language
Block Diagram TSL235R Block Diagram English
Asset Publisher