Biopotential heart rate AFE solution for wearable medical applications

Maxim Integrated’s MAX30004 biopotential AFE is now available from Mouser. 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. The device eliminates the need to extract and process 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 ESD protection, EMI filtering, and DC leads-off detection. The AFE offers extensive calibration voltages for built-in self-testing, and the device’s soft power-up sequencing ensures that no large transient signals are injected into the electrodes. The device’s fully differential input structure features high CMRR of more than 100dB and a high impedance of more than 500Mohms, which results in improved low common-to-differential mode conversion. A 0.7mA 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 device has a high DC offset range of ±650mV (1.8V typical) that allows it to be used with a wide variety of electrodes. The device offers ultra-low power consumption of just 85mW at a 1.1V supply, leading to longer battery lifetimes.