TSL237T Light-to-Frequency
High-sensitivity converter low profile 4-lead package
Features
- 5M:1 input dynamic range
- Low dark frequency (0.1Hz typical)
- High irradiance responsivity 1.2kHz/(µW/cm2) @ λp = 640nm
- 2.6mm x 3.8mm 4-lead SMD (T) package
Benefits
- Detects light intensity at a high resolution
- Provides low light level operation
- Provides for high sensitivity to detect a small change in light
- Reduces board space requirements while simplifying designs
Product parameters
Supply Voltage [V] | 2.7-5.5 |
---|---|
Responsivity [Hz/µW/cm²] | 1200 @ 640 |
Max. Output Frequency [MHz] | 1 |
Selectable Sensitivity and Full-Scale Output Frequency | |
Output Frequency Tolerances [+/- %] | 20 |
Temperature Range [°C] | -40 to 85 |
Package | T |
Remark | Not recommended for new design. Please see Ambient Light Sensors device family. |

General description
The TSL237 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. Output enable (OE) places the output in a high-impedance state for multiple-unit sharing of a microcontroller input line. 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 TSL237 is characterized for operation over the temperature range of −40°C to 85°C and is supplied in a 4-lead ChipLED package (CL) and a compact 4-lead surface-mount package (T).
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

Tools
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_TSL237T | English |
Notifications
Type | Description | Language | ||
---|---|---|---|---|
EoL Notification | Plano Test Site (issued May-20-2021) | English |
Other information
Type | Description | Language | ||
---|---|---|---|---|
Block Diagram | TSL237T Block Diagram | English |