Optical sensors deliver low power monitoring for smart devices

The sensor solutions offer best-in-class performance for headphones, fitness bands, smart watches and phones. They are integrating three LED outputs, a photodetector, a low-noise analog front-end, a digital interface and a state machine into a single die. For best application results the bare die is either packaged with an infrared or a green LED or can drive up to three external LEDs.

The sensors offer a fully integrated solution for optical heart rate measurement featuring an I²C interface for a programmable sample rate of up to 256 per second. This allows a significantly better signal-to-noise ratio (SNR) than discrete alternatives. Additionally, monitoring algorithms can filter out motion artifacts and deliver precise heart rate and pulse oximetry measurements during exercise. High optical sensor resolution enables accurate measurement across the widest possible variety of skin types, while high optical sensitivity reduces photo diode area and drives down LED power consumption with a typical 300μA LED current on fair skin. A standby current of just 0.3μA further reduces power consumption.

Infineon and GoerTek sensor solutions are available either as bare die or as packaged products with application algorithm fromInfineon’s long-term partner GoerTek. Packages measure just 3.94x2.36x1.35mm. Packaged samples are available now, with volume production targeted in August 2016. In addition to the bare die chips from Infineon, GoerTek is offering starter kits and demonstration boards for designers looking to rapidly evaluate and test the technology for use in their smart applications.