MAX30001 Biopotential and Bioimpedance Analog Front-End (AFE)

Analog Devices' MAX30001CWV+ is an analog front end (AFE) solution that includes biopotential and bioimpedance (BioZ) for wearable applications. This solution was designed for fitness and clinical applications due to the high performance and ultra-low-power, which will extend battery life. It is available in a 30 WLP and can operate over 0°C to +70°C temperature range.

The MAX30001 can provide electrocardiogram (ECG) waveforms, heart rate, and pacemaker edge detection. This device also includes a single BioZ channel capable of measuring respiration. The biopotential and BioZ channels offer high input impedance, low noise, high CMRR, programmable gain, various low-pass and high-pass filter options, and a high-resolution analog-to-digital converter (ADC). Both channels also have ESD protection, EMI filtering, internal lead biasing, DC leads-off detection, leads-on detection during standby mode, and extensive calibration voltages for built-in self-test. A soft power-up sequencing ensures no large transients are injected into the electrodes.

The biopotential channel is DC coupled and handles large electrode voltage offsets and has a fast recovery mode to quickly recover from overdrive conditions, such as defibrillation and electro-surgery. The bioimpedance channel also includes integrated programmable current drive, works with common electrodes, and has the flexibility for two or four electrode measurements. It also has AC lead-off detection.

Design Solutions - Take the Stress Out of Wearable Heart Monitoring

Features

• Clinical-grade ECG AFE with high-resolution data converter
• Better dry starts due to much improved real world CMRR and high input impedance
• Offers better common mode to differential mode conversion due to high input impedance
• High input impedance > 1 GΩ for extremely low common-to-differential mode
• Minimum signal attenuation at the input during dry start due to high electrode impedance
• High DC offset range of ±650 mV (1.8 V, typ.) allows to be used with wide variety of electrodes
• High AC dynamic range of 65 mV_PP or ECG and 100 mV_PP for BioZ will help prevent saturation in the presence of motion/direct electrode hits
• Leads-on interrupt feature allows to keep µC in deep sleep mode until valid lead condition is detected
• Built-in heart rate detection with interrupt feature eliminates the need to run HR algorithm on the μC
• Configurable interrupts allow the µC wake up only on every heart beat reducing the overall system power
• High accuracy allows for more physiological data extractions
• 32-word ECG and 8-word BioZ FIFOs allow the MCU to stay powered down for 256 ms with full data acquisition
• High-speed SPI
• Shutdown current of 0.5 µA (typ.)