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  1. #1
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    When ad7321 collects voltage, a spike voltage appears

    When AD7321BRUZ collects voltage, a spike voltage appears at the input every time it is acquired.

    After the input is opened, the ripple voltage is shown in the following figure:

    Click image for larger version. 

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    Can you explain this situation.

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  2. #2
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    Re: When ad7321 collects voltage, a spike voltage appears

    Hi,

    please use the link to the manufacturer internet site. There you get the latest and most reliable informations.

    Spike:
    This is caused by the "track and hold" capacitor and is quite usual for a SAR ADC.
    Thus often a buffer OPAMP is recommended.
    Read the datasheet "Track-and-Hold Section"

    Klaus
    Please don´t contact me via PM, because there is no time to respond to them. No friend requests. Thank you.



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  3. #3
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    Re: When ad7321 collects voltage, a spike voltage appears

    You don't show what's connected to VIN0 and VIN1. The ADC inputs are usually driven by a low impedance buffer, otherwise charge injection of the sampling switches will be observed.



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