10+ Dft Design Engineer Interview Questions and Answers

Explanation of purpose of occ controllers, scan enable signals, lock up latch and arrangement of negative and positive edge triggered flops.

• The purpose of occ controllers is to manage the clock signals in a design and ensure proper timing.

• Scan enable signals are used for testing and debugging purposes.

• Pipelined signals are used for faster data transfer while non-pipelined signals are used for simpler designs.

• Lock up latch is used to prevent race conditions between negative an...read more

Compression ratio can be tweaked by adjusting the volume of the combustion chamber. This affects fuel efficiency and power output.

• Compression ratio is the ratio of the volume of the combustion chamber at its largest to its smallest.

• Increasing compression ratio can improve fuel efficiency and power output, but too high a ratio can cause engine knocking.

• Factors that impact compression ratio include the size and shape of the combustion chamber, the size of the piston, and the st...read more

I have observed hold and setup violations in my design and took necessary actions.

• I used static timing analysis (STA) to identify hold and setup violations.

• I fixed hold violations by adding delay cells or increasing clock period.

• I fixed setup violations by reducing delay or decreasing clock period.

• I also checked for false paths and multi-cycle paths.

• I re-ran STA after fixing violations to ensure timing closure.

• I documented the changes made and communicated with the team.

• I als...read more

Resetting a tap controller without trst signals and finding coverage gaps.

• For resetting a tap controller without trst signals, we can use a power-on reset circuit or a watchdog timer.

• To find coverage gaps, we can use code coverage analysis tools like CodeSonar, Coverity, or LDRA.

• We can also use dynamic analysis tools like Valgrind or Purify to find runtime errors and coverage gaps.

• Manual testing and peer code reviews can also help in identifying coverage gaps.

• It is important ...read more

Simulation flow involves steps to run simulations, while serial simulation runs one task at a time and parallel simulation runs multiple tasks simultaneously.

• Simulation flow includes defining objectives, setting up models, running simulations, analyzing results, and making improvements.

• Serial simulation processes tasks sequentially, while parallel simulation processes tasks concurrently.

• Parallel simulation can significantly reduce simulation time compared to serial simulation...read more

I have experience with ATPG flow using tools like Synopsys TetraMAX and Mentor Graphics Tessent

• Utilized Synopsys TetraMAX for ATPG flow in previous projects

• Familiar with Mentor Graphics Tessent for ATPG

• Generated test patterns for stuck-at and transition faults

Sets are collections of distinct objects where the order does not matter.

• Sets do not contain duplicate elements

• Sets are often used in mathematics to represent groups of objects

• Sets can be manipulated using operations like union, intersection, and difference

DFT (Design for Testability) is a method used in electronics design to ensure that the product can be easily tested during manufacturing.

• DFT involves designing the product in a way that makes it easy to test for faults or defects.

• Techniques used in DFT include adding test points, scan chains, and built-in self-test features.

• DFT helps reduce the time and cost of testing during manufacturing.

• Example: Adding scan chains to a digital circuit allows for easier testing of individua...read more

Verilog code for Dft Design Engineer

• Use Verilog syntax to describe digital circuits

• Include modules, inputs, outputs, and logic gates in the code

• Ensure proper indentation and formatting for readability

Digital design problems involve challenges in designing and implementing digital circuits and systems.

• Understanding and optimizing power consumption

• Ensuring signal integrity and minimizing noise

• Implementing efficient clocking strategies

• Addressing timing issues and meeting performance requirements