General Description
The AS7057 Biosignal Sensor Analog Frontend (AFE) is the next generation Vital Sign Sensor. It
enables the user to detect biosignals such as photoplethysmogram (PPG) and pulse transit time
(PTT), as well as proximity. PPG is the most used HRM method. It measures the pulse rate - by
sampling light modulated by the blood vessels, which expand and contract as blood pulses through
them. Apart from HRM/HRV, optical Blood Pressure and SpO2 are also enabled by the two
independent working photodiode inputs of the AS7057. The AS7057 is a size and performance
optimized analog frontend to support space-limited applications such as in-ear vital sign monitoring.
The AS7057 provides three LED driver outputs, samples up to three photodiode inputs, and supports
proximity detection integrated into one of the PPG signal channels. This enables high flexibility for
several LED and photodiode arrangements in different applications. Furthermore, the AS7057
Biosignal Sensor Analog Frontend provides two ADC channels for simultaneous PPG measurements
and an automatic photodiode offset control.
The AS7057’s low-power design and small form factor are particularly well-suited for application in
earbuds, fitness bands, smartwatches, sports watches, and smart patches. In these cases, board
space is limited, and users look for extended, multi-day intervals between battery recharges. A thin
package dimension makes the AS7057 suitable for height-constrained solutions like earbuds.
Applications
Earbuds
Hearables
Optical sensor platform
Fitness band
Smart watch
Smart patches
Heart rate monitor
Cuff-less optical blood pressure measurements