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CN0350 for Piezo strain

Hi, I have read your CN0350 , it seems design for a  piezoelectric accelerometer. 

Can I use it to measure the piezoelectric  strain ? How to modify it??

Thank you so much.

Lin

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  • Hi Lin,

    The charge amplifier circuit in Figure 2 will work with a piezoelectric strain gauge, but there are several things to consider when selecting the amplifier.

    What is the bandwidth required of the circuit? This will depend on the frequency of the vibration or force applied to the sensor. The CN0350 circuit has a bandwidth of about 1MHz . It will handle signal bandwidths up to 100kHz. The gain-bandwidth product of the AD8608 is about 10MHz.

    If your sensor output frequency is less than 100kHz, then you can select from a number of CMOS op amps that have lower supply current and lower bandwidth.

    You can find the precision amplifier search table at:

    http://www.analog.com/en/products/amplifiers/operational-amplifiers/precision-amplifiers-vos-1mv-tcvos-2uv-c.html

    Sort on increasing Iq/amp and you can make the comparison between gain-bandwidth (GBW)  and supply current.

    A guideline would be to select an op amp with a GBW product at least 20 times that of the maximum signal you expect out of the sensor.

    Best Regards,

    Walt

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  • Hi Lin,

    The charge amplifier circuit in Figure 2 will work with a piezoelectric strain gauge, but there are several things to consider when selecting the amplifier.

    What is the bandwidth required of the circuit? This will depend on the frequency of the vibration or force applied to the sensor. The CN0350 circuit has a bandwidth of about 1MHz . It will handle signal bandwidths up to 100kHz. The gain-bandwidth product of the AD8608 is about 10MHz.

    If your sensor output frequency is less than 100kHz, then you can select from a number of CMOS op amps that have lower supply current and lower bandwidth.

    You can find the precision amplifier search table at:

    http://www.analog.com/en/products/amplifiers/operational-amplifiers/precision-amplifiers-vos-1mv-tcvos-2uv-c.html

    Sort on increasing Iq/amp and you can make the comparison between gain-bandwidth (GBW)  and supply current.

    A guideline would be to select an op amp with a GBW product at least 20 times that of the maximum signal you expect out of the sensor.

    Best Regards,

    Walt

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