Ams introduces ultra-thin sensors to bring new blood oxygen monitoring capabilities to earplugs, patches and other wearable devices

Ams introduces the industry's thinnest dedicated sensor for blood oxygen saturation (SpO2) measurement, enabling remote monitoring capabilities that are critical signals for small consumer products such as earplugs, smartwatches, and wristbands, as well as medical devices such as patches and oximeters.

The high performance of the new AS7038RB SpO2 sensor also means that it is suitable for innovative applications in remote diagnostic devices, such as disposable patches for SpO2 and electrocardiogram (ECG) measurements in hospital emergency rooms. This gives the healthcare team and patients greater flexibility in choosing how to measure these vital signs using non-invasive methods and how and when to respond quickly.

In fact, there is growing evidence that in some high-risk patients, low SpO2 is an early symptom of COVID-19 illness, before the onset of dyspnea. The development of the SpO2 wearable measurement device based on the AS7038RB-can be used remotely and could therefore help treat people infected with the SARS-CoV-2 virus.

Wim Renirie, vice president and general manager of ams' Accessories and Wearable Solutions business unit, said: "The introduction of the AS7038RB marks another breakthrough for ams in remote diagnostic technology. ams is actively working with a number of partners to develop innovative solutions for testing and diagnosing COVID-19. The AS7038RB provides an additional diagnostic tool that allows for the creation of wearable and disposable devices to accurately and safely monitor blood oxygen saturation without the use of a doctor."

Small size, high integration, can be used in space-limited design

The combination of the AS7038RB's small size, integrated functionality, and high-performance signal chain makes it ideal for Oems who are developing innovative applications for health monitoring in space-constrained consumer or medical products. Packaged in a 3.70mm x 3.10mm package with a thickness of just 0.65mm, the sensor integrates a high-sensitivity photodiode, four LED drivers, an analog front end and a sequencer. It comes with application software for SpO2 and heart rate measurement. The analog front end also supports concurrent ECG measurements, meeting the requirements of the IEC 6060-2-47 medical standard.

The accuracy of the AS7038RB SpO2 measurement closely matches the output of medical-grade pulse oximeters used in hospital test facilities, in part due to a unique on-wafer interference filter technology developed by ams. The filter enables the AS7038RB to capture light signals in the 590nm-710nm and most interesting near-infrared (800nm-1050nm) bands for SpO2 measurements, while blocking interference from ambient light at other wavelengths.

When combined with ams's highly sensitive photodiode, which has a large sensitive area of 2.5mm2, a high optical signal-to-noise ratio is produced. This simplifies implementation in optically challenging applications such as disposable chest strips, wristbands, and smartwatches.

The innovative flexible implementation allows for use in a wide range of applications

The AS7038RB offers drivers for up to four external leds, giving Oems the flexibility to place leds in the most suitable location for their application. This means that LED placement can be optimized for different skin thicknesses and bone structures in wrists, chest, forehead, fingers, etc.

The sensor's high sensitivity and high signal-to-noise ratio enable it to operate efficiently at the low light power emitted by leds. The integrated LED driver adjusts the drive current, so Oems can balance system power consumption and measurement performance, which helps extend the run time between battery charges in devices, such as earplugs, that contain small battery power supplies.