Vishay high-speed PIN photodiodes improve the performance of biosensors

     Vishay Intertechnology has introduced a new high-speed silicon PIN photodiode to enhance its sensitivity to visible and infrared light, broadening its optoelectronics product range. With a 4.8mm x 2.5mm rectangular top surface, a surface-mount package and an industry-low profile of 0.48mm, the Vishay Semiconductors VEMD8081 delivers a typical reverse photocurrent of 33 µA to improve biosensor performance in wearables and medical applications.

     The VEMD8081 offers 15% greater reverse photocurrent than its predecessor, the VEMD8080, while maintaining the same package size. For designers, this offers a plug-and-play alternative that can improve performance by increasing signal output, or extend battery life by reducing LED current.

     To measure heart rate in wearables such as fitness trackers and smartwatches, the VEMD8081 is placed between two green pulsating leds. The light reflected back from the skin is picked up by a photodiode and converted into an output current, which increases the sensitivity of the device and allows for more precise measurements. The rectangular shape of the VEMD8081 maximizes the area of the photodiode receiving the reflected light, thereby eliminating the waste area typically found in square photodiodes. When used in combination with red and infrared emitters, the device is ideal for SpO2 measurements in medical monitors.

     With a high sensitivity and 5.4mm² radiation-sensitive region, the VEMD8081 utilizes Vishay's proven chip technology to detect visible and near-infrared radiation in the spectral range from 350 nm to 1100 nm. For high sampling rates, the device offers fast switching times and a low capacitance of 50 pF.

     The VEMD8081 has a half-sensitivity Angle of ±65°, an operating temperature range of -40°C to +85°C, and a peak sensitivity wavelength of 840 nm. The photodiode is RoHS, halogen-free and Vishay Green compliant with J-STD-020 with a humidity sensitivity (MSL) of 3 and a floor life of 168 hours.