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Original question:

ADS131E08: Input types of delta sigma ADC

ADS131E08: Single end input measurement range

user4090349
Expert 1171 points

Part Number: ADS131E08

Hello

If use single end input of the ADC. The negative input is connect to 1/2 reference voltage. In this way, if the positive input is 0~Vref, the measurement range is -1/2ref to 1/2 ref. Only half measurement range is used. If we want to use the full measurement range, the positive input should be 3/2Vref to -1/2Vref. But due to the maximum analog input voltage limitation, -1/2Vref may not be possible. In this way, maybe the only way is to use bipolar supply with negative input connect to 0V.

Is that correct?

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  • +1
    TI__Guru 50605 points

    Hi user4090349,

    Your understanding is correct. For optimal performance, the VCM is recommended to be set at the midpoint of the analog supplies for pseudo-differential input configuration. As you can see my answers to your questions in another thread below, ±2.5V bipolar power supply is a good approach especially if your input is a bipolar single-ended input signal.

    ADS131E08: Input types of delta sigma ADC

    Could you please let me know your input signal range? Is your input an unipolar or bipolar single-ended signal? is simultaneous sampling necessary?

    Thanks&regards

    Dale