Testing and inspection

In AD converter testing, what is the main purpose of inputting a slowly varying sine wave or similar and counting how often each output code appears (a histogram)?

  1. ATo weigh the chip
  2. BTo determine linearity such as DNL and INL
  3. CTo measure power consumption
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Answer: B. To determine linearity such as DNL and INL

Feeding an ideal ADC a signal with a known distribution yields a calculable distribution of code counts. Deviations of the actual counts reveal each code's width, giving DNL and, by accumulation, INL. This is called the histogram method and is widely used to test ADC static performance.

  • A. It has nothing to do with weight.
  • B. Correct. Linearity is obtained from code counts.
  • C. Power consumption is found by measuring supply current.
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More Testing and inspection questions

  1. For a chip that failed scan testing, what is the process called that logically narrows down candidate fault locations from which outputs mismatched on which patterns?
  2. Which technique models defects such as transistor shorts and opens inside standard cells based on each cell's circuit and generates test patterns for them?
  3. Which correctly describes wafer test (probe test)?
  4. Which correctly describes the purpose of burn-in?
  5. Which correctly describes scan design, a form of design for testability (DFT)?