Product features
The TSL245 simplifies and enhances near-infrared light sensing applications by providing high-resolution sensing capability with direct microcontroller interface on a single chip. The device is compatible with IR sources ranging from 880 nm to 940 nm, and visible light is suppressed by an integral ambient light filter. It is ideally suited for transmissive or reflective measurement and detection applications - such as paper detection, proximity detection and diagnostic equipment.
TSL245 simplifies light measurement systems by eliminating the need for signal conditioning and an A/D converter.
Like the other family members - the TSL230 and the TSL235 - the TSL245 combines a photodiode and current-to-frequency converter on a single chip. It offers direct, high resolution conversion of light intensity to a digital format. This provides a simple way to process a wide dynamic range of light levels using an inexpensive microcontroller without signal conditioning circuitry or A/D converters.
The output of the TSL245 is a 50% duty cycle square wave with frequency directly proportional to the light intensity on the photodiode. The device has a 1,000,000:1 input dynamic range and a full-scale output frequency of 500 kHz. Low power consumption (5 mW) and operation down to 2.7 V make the TSL245 ideal for portable and battery powered systems.
Light-to-Frequency Summary Table 
Part number Package Response Range Features
TSL230 8-pin DIP visible Programmable sensitivity
TSL235 3 lead visible Compact, low cost
sidelooker
TSL245 3 lead infra-red Compact, low cost
sidelooker
Suggested
resale price quoted per device in quantities of 1,000
TSL245 : $1.75
Evaluation module available to support design-in
Vol 12, Summer, 1995