New Vishay Silicon PIN Photodiode Improves Sensitivity in Biomedical Applications

Vishay Intertechnology released a new silicon PIN photodiode that brings a higher level of sensitivity in the visible / near infrared wavelength to biomedical applications such as heart rate and blood oxygen monitoring. The new VEMD8082 features increased reverse light current, decreased diode capacitance, and faster rise and fall times compared to previous generation solutions. Additionally, its small form factor of 4.8 mm by 2.5 mm by 0.5 mm makes it suitable for integration into low profile devices such as smart watches.

The high sensitivity provided by the VEMD8082 is particularly important in biomedical applications such as photoplethysmography (PPG), where the photodiode is used to detect changes in blood volume and flow by measuring the amount of light absorbed or reflected by blood vessels. In such applications, precise measurements are crucial for diagnosing and monitoring conditions such as cardiovascular disease.

Specifications for the new device contributing to its high sensitivity compared to previous generation devices include a radiant sensitive area of 6.0 mm2 and an increase in reverse light current of 18 to 20 percent, depending on wavelength. Decreased diode capacitance from 50 pF to 46 pF, as well as faster rise times of 40 ns vs. 110 ns, allow for higher sampling rates.

Samples and production quantities of the VEMD8082 are available now (more info).