High-Sensitivity Light-to-Voltage Converter - The TSL257 is a high-sensitivity, low-noise light-to-voltage optical converter that combines a photodiode and a transimpedance amplifier on a single monolithic CMOS integrated circuit. The output voltage is directly proportional to light intensity (irradiance) on the photodiode. The TSL257 has a transimpedance gain of 320 Megohm. The device has improved offset voltage stability and low-power consumption and is supplied in a 3-lead clear plastic sidelooker package with an integral lens. The TSL257T is supplied in a compact 4-lead surface mount package.
High-Sensitivity Light-to-Frequency Converter - The TSL238D, TSL238T light-to--frequency converters combine a silicon photodiode and a current-to-frequency converter on a single monolithic CMOS integrated circuit. The output is a square wave (50% duty cycle) with frequency directly proportional to light intensity. Because it is TTL compatible, the output allows direct interface to a microcontroller or other logic circuitry. Both devices have been temperature compensated for the ultraviolet-to-visible range of 320 nm to 700 nm and respond over the light range of 320 nm to 1050 nm. The TSL238D is characterized for operation over the temperature range of -25 degrees C to 70 degrees C. The TSL238T is characterized for operation over the temperature of -40 degrees C to 85 degrees C.
