ADI AD5940高精度电化学测量前端解决方案

ADI公司的AD5940是高精度高阻抗低功耗电化学测量模拟前端(AFE),设计用于需要高精度基于电化学测量技术的手持应用如测量电流,伏安法或阻抗测量.和AD8233 AFE一起,AD5940在完整的生物电或生物电位测量系统用来测量皮肤阻抗和身体阻抗,还可以对电化学毒性气体进行检测.AD5940包括两个高精度激励回路和一个共通的测量通路,可使所测的传感器进行到底各种性能的测试.第一个激励回路包括一个超低功耗双输出串数模转换器(DAC),和一个低功耗低噪音电位仪.DAC的一个输出控制电位仪的非反相输入,另一个输出控制跨导放大器(TIA)的非反相输入,这种低功耗激励回路能产生DC-200Hz的信号.第二个激励回路包括12位DAC,相对比较高的速度,能产生高达200kHz的高频激励信号.AD5940测量通路具有16位800 kSPS多路逐次逼近寄存器(SAR)模数转换器(ADC),具有输入缓冲器,内置抗混淆滤波器和可编增益放大器(PGA),ADC前的输入复接允许用户选择测量输入通路,而输入通路包括多个外部电流输入,外部电压输入和内部通路,它允许内部电源电压,芯片温度和基准的诊断测量.器件工作电压2.8V-3.6V,工作温度−40℃ 到 +85℃.主要用在电化学测量,电化学气体传感器,电位仪/电流仪/伏安法/循环伏安法,生物阻抗应用如皮肤阻抗和身体阻抗,连续葡萄糖监测和电池阻抗.本文介绍了AD5940主要特性,简化框图和功能框图,ADC核框图和多种应用框图,以及EVAL-AD5940BIOZ 生物电评估板和电化学测量评估板EVAL-AD5940ELCZ主要特性,电路图和PCB设计图.
The AD5940 is a high precision, low power analog front end (AFE) designed for portable applications that require high precision, electrochemical-based measurement techniques, such as amperometric, voltammetric, or impedance measurements. The AD5940 is designed for skin impedance and body impedance measurements, and works with the AD8233 AFE in a complete bioelectric or biopotential measurement system. The AD5940 is designed for electrochemical toxic gas sensing.
The AD5940 consists of two high precision excitation loops and one common measurement channel, which enables a wide capability of measurements of the sensor under test. The first excitation loop consists of an ultra low power, dual output string, digital-to-analog converter (DAC), and a low power, low noise potentiostat...