The TSL230R, TSL230AR, and TSL230BR programmable light-to-frequency converters combine a configurable silicon photodiode and a current-to-frequency converter on single monolithic CMOS integrated circuits. The output can be either a pulse train or a square wave (50% duty cycle) with frequency directly proportional to light intensity. Device sensitivity is selectable in three ranges, providing two decades of adjustment. The full-scale output frequency can be scaled by one of four preset values. All inputs and the output are TTL compatible, allowing direct two-way communication with a microcontroller for programming and output interface. An output enable (OE) is provided that places the output in the high-impedance state for multiple-unit sharing of a microcontroller input line. The devices are available with absolute-output-frequency tolerances of 5% (TSL230BR), 10% (TSL230AR), or 20% (TSL230R). They have been temperature compensated for the ultraviolet-to-visible light range of 320 nm to 700 nm and respond over the light range of 320 nm to 1050 nm. The devices are characterized over the temperature range of 25C to 70C.