Frequently Asked DFT Interview Questions

1. Explain Launch-off-Capture. 
1. What are the Hardware modifications? (Hint: Scan Enable.)
2. Explain Launch-on-Shift.
3. Compare Launch-off-Capture Versus Launch-on-Shift in terms of Test Generation.
4. Compare Launch-off-Capture Versus Launch-on-Shift in terms of Methodology (How you pulse ? etc..).
5. Power Issues in Testing:
1. Why do we need to worry about power in Testing
2. Explain Short, Dynamic and Leakage power dissipation in CMOS.
3. Capture Power (Why is it happening? What does it affects ? Methods to control it. Limitations)
4. Shift Power (Why is it happening? What does it affects ? Methods to control it. Limitations)
6. Compare Transition delay model Versus Path Delay Model.
7. Given a circuit generate the pattern for both delay models.
8. Why Path delay model is used when we have  Transition delay model ? 
9. If you are to advise the test engineer which delay model do you prefer and why ?
10. Advantages and Dis Adv of Path delay model.
11. Hold time violation Versus Setup time Violation.
12. Given a circuit identify Hold/Setup time violation
13. How do you fix the Hold/Setup time violation
14. Explain Test Cost ?
15. JTAG Basics (TAP Controller, Inputs, 16 States etc...). 
16. Memory Testing Basics (Main components and how they interact)
17. How do you perform Binary Search in Scan chain? ( Diagnostics ) Different methods ?