阻抗测试芯片AD5933特性试验.ppt

阻抗测试芯片AD5933特性试验 1 AD5933特性 2 AD5933用途 3 AD5933框图 4 AD5933工作原理 5 AD5933试验电路图和工作原理 1 AD5933的特性 FEATURES Programmable output peak-to-peak excitation voltage to a max frequency of 100 kHz Programmable frequency sweep capability with serial I2C interface Frequency resolution of 27 bits (0.1 Hz) Impedance measurement range from 100 Ω to 10 MΩ Internal temperature sensor (±2°C) Internal system clock option Phase measurement capability System accuracy of 0.5% 2.7 V to 5.5 V power supply operation Temperature range -40°C to +125°C 16-lead SSOP package 2 AD5933的用途 APPLICATIONS Electrochemical analysis Bioelectrical impedance analysis Impedance spectroscopy Complex impedance measurement Corrosion monitoring and protection equipment Biomedical and automotive sensors Proximity sensing Nondestructive testing Material property analysis Fuel/battery cell condition monitoring 3 AD5933的系统框图 4 AD5933的工作原理 DDS信号发生器 27位计数器 12位sin，cos函数表 12位DAC 输出可设 被测电流到电压的转换 反馈电阻外接 运放偏置电压为1/2电源电压 输出增益可设定1或5 转换为电压后经低通滤波器滤波 基频频谱计算 固定采样率的12位AD变换 固定点数的基频频谱DFT计算 固定采样率固定点数DFT与可变激励频率引发的测量精度问题 5 AD5933的试验电路图和工作原理-1 USB接口+USB转UART+光电耦合 5 AD5933的试验电路图和工作原理-2 STC12C5412AD+74LS393+74HC4051+AD5933 * 600Ω 1000Ω 2400Ω 200Ω 输出阻抗 0.15mA 0.2mA 0.25mA 5.8mA 输出短路电流 0.173V 0.31V 0.76V 1.48V 输出直流偏移 0.198V 0.383V 0.97V 1.98V 输出峰峰值