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  1. #1
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    MCP3918 front end design

    Hi

    I want to design front end buffer for MCP3918. The ADC will measure dc voltage present on a capacitor.
    Voltage range is 0 - 0.1 VDC. I want to use MCP6022 op-amp

    Regards

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  2. #2
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    Re: MCP3918 front end design

    Hi,

    There is no question, thus I assume you just want general inofrmations:

    Use a non inverting OPAMP circuit.
    Gain: according input voltage range of the MCP3918.
    Gain setting resistors: anything between 1k and 10k will give good results.

    Read the OPAMP datasheet regarding ouput voltage range. If you want to measure voltages very close to 0V then the OPAMP may need negative supply voltage.

    I recommend a 100R + capacitor LPF between OPAMP_ouput and MCP3918 input.
    Capacitor value depends on the expected signal bandwidth.

    Klaus
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  3. #3
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    Re: MCP3918 front end design

    Thanks for reply.

    Should i connect pin CH0- of ADC to ground?

    Regards



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  4. #4
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    Re: MCP3918 front end design

    Hi,

    hard to say without information from your side.
    Often: yes.

    Klaus
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