The OPB780 programmable color light-to-frequency converter combines configurable silicon photodiodes and a current-tofrequency converter on single monolithic CMOS integrated circuit. The output is a square wave (50% duty cycle) with frequency directly proportional to light intensity (irradiance). The full-scale output frequency can be scaled by one of three preset values via two control input pins. Digital inputs and digital output allow direct interface to a microcontroller or other logic circuitry. Output enable (OE@) places the output in the high-impedance state for multiple-unit sharing of a microcontroller input line.