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AMC3311: Calculation of offset voltage caused by resistor accuracy

Kevin Zhang
Expert 3440 points
Part Number: AMC3311
Other Parts Discussed in Thread: ADS7957

Tool/software:

Hi Team,

The customer uses ACM3311+OP4177 (ADI)+ADS7957 to sample the voltage. AMC3311 implements isolated sampling of voltage signals and differential output; OP4177 is needed to convert the differential signal into a single-ended signal and transmit it to ADS.

1. Is this solution feasible? What are the errors of the two-stage op amp?

2. The customer's resistor accuracy is limited. When converting differential to single-ended, how should the offset voltage error caused by the resistor accuracy be calculated? Is it related to the CMRR of the op amp?

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  • 0
    TI__Expert 6415 points

    HI Kevin,

    Thank you for your question. The customer can definitely use an op amp to convert differential output to single-ended. 

    Section 8.2.2.2 of the datasheet gives guidance on how to get started for most applications:

    As far as accuracy of the differential to single-ended conversion, more specific questions on the accuracy of the op amp would be for the op amp team. Please let me know if there are any more questions.

    Also, who is the customer and what is the application?

    Best regards,

    Eva