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ADS131E08EVM-PDK: Raw Data only showing even numbers

Part Number: ADS131E08EVM-PDK

Dear Team,

a customer evaluates the ADS131E08 EVM and noticed that all raw data are even numbers.

Just some numbers as example from a full sweep (negative saturation to positive saturation):

7FFFFF
791CE2
5A7058
2D7CE2
F9951C
C6BCAA
9CFB9A
83204E
800000

This was noticed with all 8 channels.

How could this be explained?

Thanks and best regards
Martin

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  • Hi Martin,

    7FFFFF is an odd number, but I'm sure your customer is more concerned that he does not see any odd codes between +/- full-scale. For any given input voltage, we should see some level of noise that causes the last few bits toggle.

    Is your customer only taking one sample for each input voltage? Would you mind sending me a full list of several data points for a given input voltage (i.e. at least 100 points)?

    Best Regards,


     Ryan Andrews

    Precision Analog ΔΣ ADCs

  • In reply to Ryan Andrews:

    Hi Ryan,

    apologies for the late response, please find below the list of a measurement (input pins connected).

    Bit 0 is always '0'.

    Best Regards
    Martin

    FFFFFFFFFFFFF920

    FFFFFFFFFFFFF95C

    FFFFFFFFFFFFF902

    FFFFFFFFFFFFF95C

    FFFFFFFFFFFFF934

    FFFFFFFFFFFFF934

    FFFFFFFFFFFFF93E

    FFFFFFFFFFFFF952

    FFFFFFFFFFFFF916

    FFFFFFFFFFFFF8E4

    FFFFFFFFFFFFF966

    FFFFFFFFFFFFF8F8

    FFFFFFFFFFFFF90C

    FFFFFFFFFFFFF902

    FFFFFFFFFFFFF948

    FFFFFFFFFFFFF92A

    FFFFFFFFFFFFF8D0

    FFFFFFFFFFFFF93E

    FFFFFFFFFFFFF934

    FFFFFFFFFFFFF95C

    FFFFFFFFFFFFF8B2

    FFFFFFFFFFFFF93E

    FFFFFFFFFFFFF90C

    FFFFFFFFFFFFF948

    FFFFFFFFFFFFF966

    FFFFFFFFFFFFF916

    FFFFFFFFFFFFF95C

    FFFFFFFFFFFFF934

    FFFFFFFFFFFFF934

    FFFFFFFFFFFFF90C

    FFFFFFFFFFFFF92A

    FFFFFFFFFFFFF93E

    FFFFFFFFFFFFF916

    FFFFFFFFFFFFF920

    FFFFFFFFFFFFF8F8

    FFFFFFFFFFFFF902

    FFFFFFFFFFFFF93E

    FFFFFFFFFFFFF902

    FFFFFFFFFFFFF934

    FFFFFFFFFFFFF948

    FFFFFFFFFFFFF952

    FFFFFFFFFFFFF93E

    FFFFFFFFFFFFF920

    FFFFFFFFFFFFF8B2

    FFFFFFFFFFFFF9CA

    FFFFFFFFFFFFF8EE

    FFFFFFFFFFFFF97A

    FFFFFFFFFFFFF95C

    FFFFFFFFFFFFF902

    FFFFFFFFFFFFF934

    FFFFFFFFFFFFF92A

    FFFFFFFFFFFFF920

    FFFFFFFFFFFFF916

    FFFFFFFFFFFFF902

    FFFFFFFFFFFFF93E

    FFFFFFFFFFFFF8E4

    FFFFFFFFFFFFF934

    FFFFFFFFFFFFF8F8

    FFFFFFFFFFFFF948

    FFFFFFFFFFFFF902

    FFFFFFFFFFFFF920

    FFFFFFFFFFFFF90C

    FFFFFFFFFFFFF95C

    FFFFFFFFFFFFF920

    FFFFFFFFFFFFF93E

    FFFFFFFFFFFFF90C

    FFFFFFFFFFFFF8F8

    FFFFFFFFFFFFF97A

    FFFFFFFFFFFFF8DA

    FFFFFFFFFFFFF916

    FFFFFFFFFFFFF902

    FFFFFFFFFFFFF916

    FFFFFFFFFFFFF92A

    FFFFFFFFFFFFF952

    FFFFFFFFFFFFF93E

    FFFFFFFFFFFFF916

    FFFFFFFFFFFFF902

    FFFFFFFFFFFFF8F8

    FFFFFFFFFFFFF95C

    FFFFFFFFFFFFF8EE

    FFFFFFFFFFFFF952

    FFFFFFFFFFFFF934

    FFFFFFFFFFFFF93E

    FFFFFFFFFFFFF8DA

    FFFFFFFFFFFFF8F8

    FFFFFFFFFFFFF8C6

    FFFFFFFFFFFFF916

    FFFFFFFFFFFFF920

    FFFFFFFFFFFFF934

    FFFFFFFFFFFFF934

    FFFFFFFFFFFFF920

    FFFFFFFFFFFFF920

    FFFFFFFFFFFFF916

    FFFFFFFFFFFFF90C

    FFFFFFFFFFFFF8E4

    FFFFFFFFFFFFF90C

    FFFFFFFFFFFFF92A

    FFFFFFFFFFFFF948

    FFFFFFFFFFFFF916

    FFFFFFFFFFFFF916

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  • In reply to Martin Seeger:

    Thanks, Martin. I'm still looking into this and will provide an update shortly.

    Regards,

     Ryan Andrews

    Precision Analog ΔΣ ADCs

  • In reply to Ryan Andrews:

    Hi Martin,

    I still do not have an explanation for this. I have verified that, on the current version of the EVM hardware/software I'm using, I do not see this issue upon exporting the raw data to an Excel file. Can you confirm that your customer is using the same version?

    ADS131E08 Evaluation Software and Firmware Version

    Also, how are they exporting and saving the data? They should be using the Save tab, then selecting the channels and data format to save. "Data - Codes" will save the raw hexadecimal ADC output.

    Status Bits CH1
    FFFFFFFFFFC00FF0 FFFFFFFFFFFFF84D
    FFFFFFFFFFC00FF0 FFFFFFFFFFFFF845
    FFFFFFFFFFC00FF0 FFFFFFFFFFFFF83B
    FFFFFFFFFFC00FF0 FFFFFFFFFFFFF84C
    FFFFFFFFFFC00FF0 FFFFFFFFFFFFF854
    FFFFFFFFFFC00FF0 FFFFFFFFFFFFF836
    FFFFFFFFFFC00FF0 FFFFFFFFFFFFF852
    FFFFFFFFFFC00FF0 FFFFFFFFFFFFF862
    FFFFFFFFFFC00FF0 FFFFFFFFFFFFF85F
    FFFFFFFFFFC00FF0 FFFFFFFFFFFFF850
    FFFFFFFFFFC00FF0 FFFFFFFFFFFFF851

    Best Regards,


     Ryan Andrews

    Precision Analog ΔΣ ADCs

  • In reply to Ryan Andrews:

    Hi Ryan,

    yes, the customer confirmed that they use the same software version and did the same to export the data.

    Please find below some more values from the export:

    Record #:  0
    Notes :
    21-6-201711:10:27
    Codes Data
    Status Bits CH1
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF90C
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF8F8
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF90C
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF92A
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF8F8
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF916
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF920
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF952
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF90C
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF934
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF934
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF916
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF92A
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF934
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF948
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF916
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF934
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF93E
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF920
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF920
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF8EE
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF966
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF8F8
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF920
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF95C
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF948
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF93E
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF916
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF90C
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF916
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF920
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF8B2
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF9F2
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF8EE
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF916
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF934
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF98E
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF95C
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF90C
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF970
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF93E
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF948
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF93E
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF934
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF92A
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF95C
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF920
    FFFFFFFFFFC00FE0 FFFFFFFFFFFFF920

    A difference I saw between your export and the customer's is a status bit - is this the IN1N_FAULT?

    Best Regards

    Martin

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  • In reply to Martin Seeger:

    Hi Martin,

    Yes - the only difference appears to be that "IN1N_FAULT" is set to '1' on my EVM. Not sure why, but that should have no effect on the channel data.

    I'm honestly at a loss for suggestions. Has the customer tried multiple EVMs?

    Best Regards,


     Ryan Andrews

    Precision Analog ΔΣ ADCs