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Thursday 4 March 2010

VLSI Interview Questions-1

  1. what is the difference between mealy and moore state-machines
  2. how to solve setup and hold violations in the design
  3. what is antenna violation & ways to prevent it
  4. we have multiple instances in RTL(Register Transfer Language), do you do anything special during synthesis stage
  5. what is tie-high and tie-low cells and where it is used
  6. what is the difference between latches and flip-flops based designs
  7. what is High-Vt and Low Vt cells
  8. what is LEF mean?
  9. what is DEF mean?
  10. steps involved in designing an optimal padring
  11. what is metastability and steps to prevent it
  12. what is local-skew, global skew and useful skew
  13. what are the various timing-paths which i should take care in my STA runs?
  14. what are the various components of leakage-power
  15. what are the various yield losses in the design
  16. what is meant by virtual clock definition and why do i need it
  17. what are the various variations which impacts timing of the design
  18. what are the various Design constraints used, while performing synthesis for a design
  19. specify few verilog constructs which are not supported by the synthesis tool
  20. what are the various capacitances with an MOSFET?
  21. Vds-Ids curve for an MOSFET, with increasing Vgs
  22. explain basic operation of an MOSFET
  23. what is channel length modulation
  24. what is body effect
  25. what is latchup in CMOS design and ways to prevent it?
  26. what are the various design changes you do to meet design power targets
  27. what is meant by library characterization
  28. what is meant by wireload model
  29. what are the measures to be taken to design for optimized area
  30. what all will you be thinking while performing floorplan
  31. what are the measures in the design taken for meeting signal integrity targets
  32. what are the measures taken in the Design achieving better yield
  33. what are the measures or precautions to be taken in the design when the chip has both analog and digital portions.
  34. what are the steps incorporated for Engineering Change order[ECO]
  35. what are the steps performed to achieve Lithography friendly Design
  36. what does synthesis mean?
  37. what are the pre-requistes to perform synthesis
  38. can you explain the synthesis flow
  39. what are the various ways to reduce clock insertion delay in the design
  40. what are the various functional verification methodologies
  41. what does formal verification mean
  42. how will you time the output path in STA
  43. how will you time the input path in STA
  44. what is false path mean in STA and in what scenarios falsepath can come
  45. what does multicycle path mean in STA and in what scenarios MCP can come
  46. what are source synchronous paths in STA
  47. Assume there is a specific requirement to preserve the logic during synthesis , how will you achieve it.
  48. we have multiple instances in RTL, do you do anything special during synthesis stage
  49. what do you call an event and when do you call an assertion.
  50. what is difference between FPGA and ASIC.
Solutions to these questions will be provided on request.


  1. I had received ans from vishal. explanation is good for all questions.it was helpful.

    thanks vishal

  2. These are really nice interview questions for VLSI .... thanks a lot

  3. Great collection, it will be helpful if u can provide the answers

  4. I receied answers & it was informative. thank you


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