Testing and inspection

Which correctly describes scan design, a form of design for testability (DFT)?

  1. AScanning the chip surface with an optical microscope to find defects
  2. BGradually raising the supply voltage during test to find the operating limit
  3. CConnecting the flip-flops in a circuit like a shift register to make it easy to set and observe internal states
Show answer and explanation

Answer: C. Connecting the flip-flops in a circuit like a shift register to make it easy to set and observe internal states

In scan design, the circuit's flip-flops are chained together (scan chains) during test so that arbitrary values can be set from outside and internal values can be read out. This allows efficient testing of the combinational logic and enables automatic test pattern generation (ATPG).

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More Testing and inspection questions

  1. Which items are mainly checked in a semiconductor DC test?
  2. Which correctly describes BIST (built-in self-test)?
  3. Which correctly describes a probe card?
  4. Which correctly describes the stuck-at fault model used in testing logic circuits?
  5. Which is the correct definition of fault coverage for test patterns?