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ADS8382: Can the differential input be changed to a single-ended input?

aiwen chen
Intellectual 625 points
Part Number: ADS8382
Other Parts Discussed in Thread: ADS8380, ADS8381

I WANT TO INCREASE THE SAMPLING ACCURACY TO 5PPM，If I use an   fully differential ADC like   ADS8382 and  change the differential input to a single input, -IN is connected to analog ground.

Can a fully differential input   ADC be used as a single input ADC? If it is used as a single  ADC, Is it different from an ADC that is originally a single input?  

Does it have an impact on sampling accuracy?  Change  fully differential input   to a single  input, will its accuracy be higher than that of a normal single  ADC?

  • 0
    TI__Guru 63906 points

    Hi Aiwen,

    Thank you for your post and please excuse the delay. I'm looking into your question and will get back to you tomorrow with a more detailed response.

    Regards,

    Ryan

  • 0 in reply to Ryan Andrews
    TI__Guru 63906 points

    Hi Aiwen, 

    After looking at this device more closely, it appears that the expected input signal type is fully-differential. There are a couple points in the data sheet to note. First, take a look at the input common-mode voltage on page 3. The common-mode voltage is specified as VREF/2 +/- 0.2 V. These means that the ideal input common-mode is exactly 0.2 V and should remain constant. This would not be satisfied with a single-ended input signal.

    Secondly, look at Figure 53. Here, the suggested input circuit is used to convert a single-ended input signal to fully-differential. This type of circuit could be used to set the common-mode as needed.

    A more appropriate device from this family of products would be either the ADS8380 or ADS8381, depending on the required interface type.

    Regards,

    Ryan