AD/DA conversion

What is an advantage of using a differential input for an AD converter?

  1. AThe circuit always becomes simpler
  2. BPower consumption always becomes zero
  3. CCommon-mode noise is easily canceled, and a larger signal swing can be handled
Show answer and explanation

Answer: C. Common-mode noise is easily canceled, and a larger signal swing can be handled

With a differential input, the voltage difference between two signal lines is converted, so noise appearing equally on both (common-mode noise) cancels. It also handles twice the swing of a single-ended input at the same supply voltage, making it easier to raise SNR. Most high-performance ADCs use differential inputs.

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More AD/DA conversion questions

  1. In a delta-sigma AD converter, which digital circuit converts the fast, coarse quantized output into high-resolution data at a lower sampling rate?
  2. What is the brief spike-like error that appears at the output of a DA converter at the moment the input code changes?
  3. Which architecture runs several AD converters alternately with slightly staggered timing to achieve a high overall sampling rate?
  4. What is the main reason for placing a driver circuit, such as an op-amp, in front of a successive-approximation AD converter?
  5. Which architecture is used as the internal DAC in many successive-approximation AD converters?