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.

Features

Three LED drivers and three photodiode input

pins.

Small Wafer-Level-Chip-Scale-Package

WLCSP).

Two synchronized PPG acquisition channels.

Two independent, programmable sequence

blocks inside the PPG signal acquisition.

Low noise analog optical frontend.

Hardware sequencer to offload processor.

Adjustable LED driver with current control.

Applications

● Earbuds

● Hearables

● Optical sensor platform

● Fitness band

● Smart watch

● Smart patches

● Heart rate monitor

● Cuff-less optical blood pressure measurements