TSL245A

Overview

The TSL245 is an infrared light-to-frequency converter integrating a silicon photodiode and current-to-frequency converter on a monolithic CMOS IC. It outputs a square wave with frequency directly proportional to light intensity, enabling direct microcontroller interface. The device operates on a single supply from 2.7 V to 6 V. It responds to infrared light between 800 nm and 1100 nm. Key electrical parameters include a full-scale frequency of 500 kHz, typical nonlinearity error of 0.2% at 100 kHz, and supply current of 3 mA at 5 V.

Feature Summary

• Integral visible-light cutoff filter for infrared response (800 nm–1100 nm)
• TTL-compatible output for direct logic interfacing
• Single-supply operation down to 2.7 V
• No external components required for conversion

Applications

• Microcontroller-based optical sensing systems
• Infrared irradiance measurement
• Light exposure integration monitoring

Procurement Notes

Verify the specific package configuration against the datasheet Figure 1 dimensions. Confirm that the operating temperature range meets the application requirement of –25 °C to 70 °C. Ensure power-supply decoupling capacitors (0.01 μF to 0.1 μF) are included in the design for optimal performance.

Selection Notes

Select this component when a compact, three-terminal solution for converting infrared light intensity to a digital frequency signal is required. It is suitable for applications needing high resolution without external analog components. Consider the 500 kHz maximum frequency limit and the specific spectral responsivity curve for wavelength accuracy.

Part Context

The TSL245 utilizes Texas Instruments' Advanced LinCMOS technology. It combines a photodiode and signal processing circuitry into a single monolithic integrated circuit. This integration eliminates the need for external amplifiers or filters, simplifying the design of infrared detection circuits.

Replacement Considerations

Publicly confirmed substitute part numbers are not available in the provided documentation.

FAQ

What is the spectral response range of the TSL245?

The device responds over the infrared light range of 800 nm to 1100 nm.

How is the output frequency related to light intensity?

The output is a square wave with a frequency directly proportional to the incident light intensity.

What is the typical nonlinearity error?

The nonlinearity error is typically 0.2% at 100 kHz.