VLSI interview question and answers, VLSI interview Question with Answers, VLSI Interview Questions
Hi, Today i would like to share some more VLSI interview Question and answers.
1. What do you mean by metastability?
When setup or hold window is violated in the flip flop then signal attains a unpredictable value or state which is known as metastability.
2. What is an MTBF? What it signifies?
- MTBF- stand for Mean Time Before Failure
- IT signifies Average time to next failure
3. How chance of the metastable state failure can be reduced?
The chance of Metastable state failure can be Reduced By
- Lowering clock frequency
- Lowering data speed
- Using faster flip flop
4. What are advantages of using synchronous reset ?
- No metastability problem with the synchronous reset (provided recovery and removal time for reset is taken care).
- Simulation of the synchronous reset is easy.
5. Give the disadvantages of using synchronous reset ?
- The Synchronous reset is slow.
- Implementation of synchronous reset requires more number of gates compared to the asynchronous reset design.
- An active clock is essential for the synchronous reset design. Hence you can expect more power consumption.
6. What are the advantages of using the asynchronous reset ?
- Implementation of asynchronous reset requires less number of gates compared to the synchronous reset design.
- The Asynchronous reset is fast.
- Clocking scheme is not necessary for an asynchronous design. Hence the design consumes less power. Asynchronous design style is also one of latest design options to achieve low power. Design community is scrathing their head over asynchronous design possibilities.
7. What are the disadvantages of using the asynchronous reset ?
- Metastability problems are the main concerns of asynchronous reset scheme (design).
- The Static timing analysis and DFT becomes difficult due to asynchronous reset.
8. What are the 3 fundamental operating conditions that determine delay characteristics of gate? How operating conditions affect gate delay?
- Process
- Voltage
- Temperature
9. Is verilog/VHDL is concurrent or sequential language?
- The Verilog and VHDL both are concurrent languages.
- Any hardware descriptive language is concurrent in nature.
10. In a system with insufficient hold time, will slowing down clock frequency help?
- No.
- Making data path slower can help hold time but it may result in the setup violation.
11. In a system with the insufficient setup time, will slowing down the clock frequency help?
- Yes.
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