General description
The AS7058 is an integrated multi-vital sign monitoring device, which provides a complete photoplethysmogram (PPG), electrocardiogram (ECG), body impedance (BioZ), and electrodermal activity (EDA). PPG measures the pulse rate or blood oxygen by sampling light modulated by the blood vessels, which expand and contract as blood pulses through them. ECG is the reference for any measurement of the biopotential generated by the heart. With EDA, it is possible to measure the skin’s water content, and with BioZ, the body composition with an electrical system.
The PPG acquisition system provides up to eight LEDs and eight photodiode inputs. The LEDs are powered by two high current 8-bit programmable LED drivers with four current ranges. Additionally, a special laser safety support system can be enabled, which offers the possibility to use VCSEL die as a light source. The photodiodes can be read out synchronously with two 20-bit ADCs. As the second product in the AS705x family, the AS7058 includes a new method of ambient light suppression method called advanced automatic offset control (AAOC). This method enables the system to adjust towards the ambient light situation before the actual measurement starts and minimizes the loss of data due to the saturation influence by ambient light.
The ECG channel has high-input impedance, low noise, high CMRR, programmable gain, an anti-aliasing low-pass filter, and a high-resolution 20-bit ADC. It is designed according to IEC 60601-2-47 Ambulatory ECG Systems monitoring compliance requirements.
The BioZ channel has a low-pass filter and a calibration routine available. The channel also has high input impedance, low noise, programmable gain, low-pass and high-pass filter options, and shares the high-resolution ADC with the ECG system. Several ranges of excitation current and frequencies are also available.
The AS7058 has a DC and AC lead-off detection for the ECG, a flexible clock system, and a PLL. All three inbuilt ADCs are synchronized. The device is available in a 42-ball wafer-level chip scale package (WLCSP) with dimensions 2.82 mm x 2.55 mm and operates over the temperature range -40 °C to 85 °C.
Applications
Wearable vital sign monitors
Fitness band
Smart watch
Heart rate monitor
Hearables
ECG monitoring
Medical patches
Pulse-oximetry devices
Single- and multi-frequency body impedance devices
Pulse Arrival Time (PAT), Pulse Transit Time (PTT), Pulse Wave Velocity (PWV) Assessments