PIN Photodiode Enables Slimmer Wearables

(Vishay Intertechnology)

Vishay Intertechnology's latest silicon PIN photodiode, the VEMD8080, features a rectangular 4.8 mm by 2.5 mm top-view, surface-mount package with a 0.48-mm profile, allegedly 0.37-mm lower than competing devices. The VEMD8080 offers fast switching times and a capacitance of 47 pF.

 

With a radiant-sensitive area measuring 4.5 mm², radiant sensitivity with a reverse light current of 28 µA, and a dark current of 0.2 nA, the device detects visible and near infrared radiation over a range from 350 nm to 1100 nm. For green LEDs, its sensitivity represents a 30% improvement over the standard technology in previous-generation solutions.

 

Used with green LEDs, the photodiode's small size enables slim sensor designs for optical heart rate detection in wearable devices such as fitness trackers and smartwatches. In these devices, the VEMD8080's rectangular shape allows several light emitting diodes to be placed close to the radiant sensitive area to maximize the signal. When combined with 660 nm and 940 nm dual color emitting diodes, the photodiode is viable for SpO2 measurement in medical monitors.

 

Other features include a ± 65° angle of half-sensitivity, operating temperature range of -40°C to +85°C, and 950 nm wavelength of peak sensitivity. Price starts at $0.55 per piece. Checkout the VEMD8080 datasheet.