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ADC with really "True differential input"

vlad8016
on Nov 18, 2015

Hi collegues.

I need ADC with really differential input and single supply.

-IN connected to reference point (REF/2)

+IN connected to input signal (+\- 2.5v)

I tried AD7684 but DataSheet tells that +IN and -IN MUST be in opposite phase to reference point. I used MCP3301 which is pin2pin compatible with AD7684 but allow any signals on inputs.

Now we need 500kS ADC and MCP3301 couldn`t achieve this.

Could you advice ADC or solution for AD7693 to adapt it to described use case.

Thank you in advance.

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  • 0 on Nov 19, 2015 2:24 PM over 5 years ago

    Thank you for replies.

    As I see in data sheet ADC with pseudo-differerential input couldn`t convert voltage below GND.

    For example AD7694. -IN should be connected to GND, and +IN should be between GND and VREF.

    So I can't convert negative voltage. If it is right I don`t understand real difference between pseudo-differential and single-ended. In pseudo-differential ADC -IN could be connected to GND+\- 0.1v and that`s all?

    May be I`m wrong?

Reply
  • 0 on Nov 19, 2015 2:24 PM over 5 years ago

    Thank you for replies.

    As I see in data sheet ADC with pseudo-differerential input couldn`t convert voltage below GND.

    For example AD7694. -IN should be connected to GND, and +IN should be between GND and VREF.

    So I can't convert negative voltage. If it is right I don`t understand real difference between pseudo-differential and single-ended. In pseudo-differential ADC -IN could be connected to GND+\- 0.1v and that`s all?

    May be I`m wrong?

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