Analog Devices, Inc. announced recently a new electrochemical & impedance measurement front end that enables the next generation of vital sign monitoring devices and intelligent electrochemical sensors. The AD5940 analog front end incorporates both potentiostat and electrochemical impedance spectroscopy (EIS) functionality on a single chip, allowing for sensor measurement in both time and frequency domains. The device features integrated hardware accelerators for advanced sensor diagnostics, best-in-class low noise for accurate sensor measurements and is designed for wearable “always-on” applications. Compared to traditional discrete solutions which pose limitations and require multiple ICs to achieve similar performance, ADI’s single chip solution offers advantages in terms of system accuracy and size flexibility to measure 2-Lead, 3-Lead and 4-Lead electrochemical sensors. It’s an ideal solution for applications, where high precision biological and chemical sensing is mission-critical, such as industrial gas sensing, liquid analysis, material sensing, vital signs monitoring, impedance spectroscopy and disease management.
The AD5940 is the lowest power, highest performance Impedance and electrochemical front end with intelligent autonomous control. The analog front end combines leading levels of integration and performance for potentiostat and impedance-based electrochemical sensor managements. The on-chip potentiostat allows for a host of standard electrochemical-based measurement techniques, such as amperometric, voltametric, or impedance measurements.The AD5940 is designed to be used in healthcare-related bio-impedance systems for both skin impedance and body impedance measurements, and also to work with the AD8233AFE in a complete bioelectric/biopotential measurement system.
The analog front end chip can measure Voltage, current and impedance. The device consists of two potentiostat loops, a low bandwidth loop with ability to generate AC signals up to 200 Hz and a high bandwidth loop with ability to generate AC signals up to 200kHz. The ultra-low power Potentiostat consumes 6.5uA in biased mode. The AD5940 measurement blocks can be controlled via direct register writes through the Serial Peripheral Interface (SPI) interface, or alternatively, by using a pre-programmable sequencer, which provides autonomous control of the AFE chip. 6 kB of static random access memory (SRAM) is partitioned for a deep data first in, first out (FIFO) and command memory.
For more information