AFE enables wearing your heart rate on your sleeve

20th August 2017

Mick Elliott

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Datasheet

The MAX30004 biopotential analogue front-end (AFE) from Maxim Integrated is in stock at Mouser Electronics. The device is a single-channel biopotential heart-rate detection AFE solution for wearable medical applications, such as chest bands and single-lead wireless patches for heart rate monitoring. It eliminates the need to extract and process electrocardiogram (ECG) data on its microcontroller for high-motion environments.

The AFE provides a single biopotential channel that measures R wave-to-R wave interval of heart beats to determine heart rate. The biopotential channel features electrostatic discharge (ESD) protection, electromagnetic interference (EMI) filtering, and DC leads-off detection.

The device offers extensive calibration voltages for built-in self-testing, and its soft power-up sequencing ensures that no large transient signals are injected into the electrodes.

A fully differential input structure features high common-mode rejection ratio (CMRR) of more than 100dB and a high impedance of more than 500MOhms, which results in improved low common-to-differential mode conversion.

A 0.7 mA leads-on feature keeps the AFE’s microcontroller in deep sleep mode, with the real-time clock in the off position until a valid lead condition is detected.

Configurable interrupts allow the microcontroller to wake up only on every heartbeat, reducing overall system power consumption.

The MAX30004 has a high DC offset range of ±650 mV (1.8 V typical) that allows it to be used with a wide variety of electrodes. The device offers ultra-low power consumption of just 85 mW at a 1.1 V supply, leading to longer battery lifetimes.