Light-to-Frequency Converter Boasts High Sensitivity

Jan 3, 2006 5:25 PM

Designers can now measure extremely low levels of light in low-profile applications that require surface-mount packages with the new light-to-frequency converter from Texas Advanced Optoelectronic Solutions. Packaged in an 8-pin SOIC surface-mount package, the TSL238 High-Sensitivity Light-to-Frequency Converter can accurately measure a broad dynamic range of light levels from bright sunlight to dim moonlight.

The TSL238 does not require an external analog-to-digital converter because its output is a waveform whose frequency is directly proportional to the light intensity, thereby enabling the device to interface directly to a microprocessor. This latest TAOS light-to-frequency converter also has an output enable pin that provides the designer with the option of feeding the output of multiple devices into a single microprocessor input port by enabling one TSL238 device at a time.

The TSL238 High-Sensitivity Light-to-Frequency Converter is suitable for medical applications measuring low-levels of fluorescent, reflective and transmissive light, such as that found in pulse oximetry systems. The TSL238 has a wide dynamic range of more than 90 dB at room temperature and features an extended temperature range of -25°C to 70°C. It has been temperature compensated for the ultraviolet-to-visible light range of 320 nm to 700 nm, and responds over the light range of 320 nm to 1050 nm.

The TSL238 is housed in an 8-pin SOIC surface-mount package and has a suggested resale price of $1.72 in 1000-piece quantities.