The device converts light intensity into a frequency with no need for external components. It has a high irradiance responsivity of 3.4kHz/(microW/cm2) at a wavelength of 640nm. Other characteristics include a low dark frequency of less than 6Hz at 50°C, a 200ppm/°C temperature coefficient for stability, and operation from a 2.7 to 5.5V single supply over the temperature range of –25 to 70°C. The RoHS compliant chip combines a silicon photodiode and a current-to-frequency converter on a single monolithic CMOS integrated circuit. Its 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 to 700nm and responds over the light range of 320 to 1050nm. It is supplied in a compact 4-lead surface-mount package.