A clinical-grade analogue front end (AFE) from Maxim Integrated, now part of Analog Devices, can measure four vital signs for remote patient monitoring devices.

The Max 86178 features synchronised measurement of electrocardiogram (ECG), heart rate, SpO₂ and respiration rate to simplify the design of wearable remote patient monitoring (RPM) devices.

This single-chip AFE integrates three measurement systems – optical, ECG and bio-impedance – to obtain four common vital signs: ECG, heart rate (ECG or optical PPG), blood-oxygen saturation (SpO₂) and respiration rate (using BioZ). The device enables synchronised optical PPG and ECG timing for derived health metrics.

Medical device designers are eager to reduce annual healthcare-related expenditures by replacing office-based health monitoring systems with smaller, lower power, wireless devices worn discreetly and continuously in the home or office. With three clinical-grade subsystems integrated into one IC, the triple system AFE replaces discrete implementations by integrating an optical PPG subsystem to measure heart rate and SpO₂, a single lead ECG subsystem, as well as a biopotential and bioimpedance (BioZ) subsystem to measure respiration rate. It permits small vital signs devices by fitting those multiple functions into a 2.6 by 2.8mm package.

In addition, wearable RPMs will need to operate at low power to permit smaller batteries or extend battery life to allow more convenient charging requirements. To enable low-power features, the device provides each subsystem with configurable options to optimise battery life for specific use cases.

“By integrating three healthcare subsystems on one piece of silicon, Analog Devices builds on its DNA and delivers this sensor-fusion product,” said Andrew Burt, executive business manager at California-based Maxim Integrated. “This AFE is resonating with the medical community because it presents new possibilities for chronic disease management, contagious disease diagnosis and remote monitoring. The Max 86178 enables small body-worn devices that can improve healthcare delivery and lower costs by keeping people out of the hospital.”

• The Max 77659 single-inductor multiple output (SIMO) power management IC (PMIC) with integrated switch-mode buck-boost charger from Maxim Integrated charges wearables, hearables and IoT devices at a speed said to be faster and in less space than any other PMIC available today.

The device delivers over four hours of play time after a short, ten-minute charge, and uses a single inductor to power multiple rails, reducing the bill of materials by 60 per cent and shrinking total size by half.

It integrates a switch-mode buck-boost charger and three independently programmable buck-boost regulators, all sharing a single inductor to reduce size. The regulators extend battery life by operating at 91 per cent efficiency during moderate to heavy load conditions while consuming 5µA of quiescent current during light load conditions.

The PMIC supports autonomous headroom control, which lowers heat dissipation by reducing the voltage drop while providing enough headroom to regulate the charging current.

“Analog Devices’ SIMO product technology shrinks size and boosts performance in the smallest of hearable and wearable devices,” said Roger Yeung, executive business manager at Maxim Integrated. “The Max 77659 brings the on-the-go lifestyle to the next level by minimising plug-in time and maximising play time. The Max 77659 PMIC frees up board real estate to pack in additional features such as expanded memory storage, location tracking and vital sensing demanded by today’s portable consumer and medical devices.”