Vishay's new silicon PIN photodiode improves sensitivity in biomedical applications

     Vishay Intertechnology, Inc. announced the launch of a new silicon PIN photodiode, the VEMD8082, that provides increased sensitivity in visible/near-infrared wavelengths for biomedical applications such as heart rate and blood oxygen monitoring. Compared to previous generations of solutions, the newly introduced VEMD8082 features higher reverse photocurrent, lower diode capacitance, and faster rise and fall times. In addition, the device size is as small as 4.8 mm x 2.5 mm x 0.5 mm, which is suitable for integration into thin and light devices such as smart watches.

     The VEMD8082's high sensitivity is typically used in biomedical applications such as photovolumetric pulse wave (PPG), where photodiodes are used to detect changes in blood volume and flow by measuring the amount of light absorbed or reflected by blood vessels. In these application areas, accurate measurements are essential for diagnosing and monitoring diseases such as cardiovascular disease.

     Compared to the previous generation, the new device is highly sensitive due to its 6.0 mm2 radiation-sensitive area and an 18-20% increase in reverse photocurrent (depending on wavelength). The diode capacitance is reduced from 50 pF to 46 pF, and the rise time is faster, from 110 ns to 40 ns, allowing for higher sampling rates.