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LTC1966输入隔直电容多大合适?

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The user is designing a circuit to measure the RMS value of a sine wave signal (0-1V, 10Hz-1000KHz) using the LTC1966 with R1=R2=100KΩ and VDD=5V. The final answer suggests an input impedance of 8MΩ and recommends a Cc value of 22nF. Accompanying answers clarify that achieving 0.1% precision across the entire frequency range is challenging, especially at higher frequencies, and suggest using a higher Cc value (22uF) for better low-frequency performance. The user also inquires about the input impedance equivalence and the feasibility of using AD637 for lower power consumption in a 4-20mA application.
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Category: Datasheet/Specs
Product Number: LTC1966

上图是从LTC1966规格书里面摘录出来的,我现在的设计和该图一致,R1=R2=100K,VDD=5V,但是不Cc不知道该如何选?我现在要求测量10Hz-1000KHz,峰值电压为0-1V以内的正弦波信号的有效值,精度希望能达到0.1%,担心Cc太小会导致低频误差增大,请给我下设计规范。

Parents
  • 频率范围改为为10Hz-1000Hz,适配机械简谐振动的测量;另外,我输入是接在IN1端,分压电阻在IN2端,为什么输入阻抗等效为R1//R2,看起来IN1和IN2毫无关系。AD637对我应用来说功耗还是太高了,我的应用是用4-2mA供电,做的是机械速度有效值的测量。目前用了ADXL1002、积分器、LTC1966、4-20mA驱动电路来做的设计。

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  • 频率范围改为为10Hz-1000Hz,适配机械简谐振动的测量;另外,我输入是接在IN1端,分压电阻在IN2端,为什么输入阻抗等效为R1//R2,看起来IN1和IN2毫无关系。AD637对我应用来说功耗还是太高了,我的应用是用4-2mA供电,做的是机械速度有效值的测量。目前用了ADXL1002、积分器、LTC1966、4-20mA驱动电路来做的设计。

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