Low-Power, High-Performance Bioimpedance Analog Front-End

The MAX30009 is a complete Bioimpedance (BioZ) Analog Front-End (AFE) solution for wearable applications. It offers high performance for fitness, wellness, and clinical applications, and ultra-low power for long battery life. The BioZ receive channel has Electrostatic Discharge (ESD) protection, Electromagnetic Interference (EMI) filtering, internal lead-biasing, DC leads-off detection, DRVN lead-off detection, and ultra-low power lead-on detection during standby mode. The BioZ receive channel also has high input impedance, low noise, high Common-Mode Rejection Ratio (CMRR), programmable gain, various low-pass and high-pass filter options, and two high resolution analog-to-digital converters for simultaneous I and Q acquisition.

The BioZ transmit channel has a sine-wave current generator to drive AC currents into the body with a wide frequency range of 16Hz to 500kHz and a wide magnitude range of of 16nARMS to 1.28mARMS. The transmit channel can also operate in the sine-wave voltage and H-bridge modes. The flexible input/output MUX allows for both bipolar and tetrapolar measurements with multiple sets of electrodes.

For measurements requiring high absolute impedance accuracy such as Bioimpedance Analysis/Spectroscopy (BIA/BIS) and Automated External Defibrillator (AED) body impedance, the MAX30009 offers several calibration options. An external precision resistor can be connected to the four-wire calibration port for the highest accuracy. Internal trimmed resistors also provide high accuracy.

The PLL-based timing subsystem allows for a wide range of fine-tuned stimulus and sampling frequencies, and can be synchronized with other Analog Devices biosensors for simultaneous data collection.

The MAX30009 is available in a 2.03mm x 2.03mm, 25-bump Wafer-Level Package (WLP), operating over the -40°C to +85°C temperature range.

Applications

* Wearable Fitness, Wellness, and Medical Devices

* Multifrequency Body Composition Analyzers

* Non-Invasive Hemodynamic Monitors

* Automatic External Defibrillators

* Optimized Performance to Accurately Detect:

* Respiration Rate

* Galvanic Skin Response/Electrodermal Activity

* Bioimpedance Spectroscopy

* Body Composition and Fluid Analysis

* Impedance Cardiography and Plethysmography

* BIOZ

* Complete High-Performance BioZ AFE

* Simultaneous I and Q Measurement Capability

* Four-Electrode (Tetrapolar) and Two-Electrode (Bipolar) Configurations

* Ultra-Low Power Operation

* 250 µW at 1.8V AVDD

* High-Resolution, 20-Bit Sigma Delta Analog-to-Digital Converters (ADCs)

* Wide Range of Sample Rates from 16sps to 4ksps

* Flexible and Programmable Input/Output MUX

* Low-Noise, High-Resolution Receive Channel

* 17 Bits Effective Resolution with 1.1ΩVP-P Noise

* High Input Impedance > 1GΩ for Extremely Low Common to Differential-Mode Conversion

* Programmable Sine-Wave Stimulus

* Low Frequency, Low Current Options for Galvanic Skin Response (GSR)/Electrodermal Activity (EDA) Starting from 16Hz and 16nARMS

* Wide Range of Bioelectrical Impedance Analysis/Spectroscopy (BIA/BIS) Frequencies from 1kHz to 806kHz

* High Currents at High Frequencies for Impedance Cardiography (ICG) Applications (e.g.,1.28mARMS at 100kHz) with Lockout for Lower Frequencies for Conformance with 60601-1

* High Input AC Dynamic Range of >1000mVP-P

* 4-Pin In-Situ Calibration Port (4-Wire Precision Resistor) Enables High-Quality Absolute Impedance Measurements

* DC Leads-Off Detect Capability

* Ultra-Low Power Lead-On Detection with Interrupt for System Wake-Up

* Lead-On Detect Current: 0.7µA (typ)

* SYSTEM

* Shutdown Current of 0.6µA (Typ)

* 256 Word FIFO

* Flexible PLL-Based Timing Subsystem with Internal or External Clock Source

* PLL can be Synchronized with Adjacent Biosensor AFEs (such as the MAX86176 Photoplethsymography (PPG)/Electrocardiography (ECG) AFE)

* Configurable Interrupts Reduce µC Wake-Up Time and Save Power

* High-Speed Serial Peripheral Interface (SPI) and I2C Digital Interface