The company visited our campus for three hardware roles: Physical Design, SOC Verification, and FPGA Design.

I was interviewed by the SOC Verification team.

Round 0 - Online Assessment (with negative marking)

• Section A - Aptitude: 30 minutes, 20 questions. Easy to moderate level.
• Section B - C Programming: 30 minutes, 20 questions. Moderate level.
• Section C - Digital: 30 minutes, 20 questions. Moderate to hard level.

Round 1 - 20 minutes approx.

• Asked to introduce myself.
• Discussion on my projects.
• Told about the role they came for and asked if I was okay with that role.
• Why Qualcomm and where do I see myself or what are my career plans for the next 5 years.
• Asked array-based C programming questions, such as merge sort algorithm, finding the second largest element in an array, and time complexity.

Round 2 - 40 minutes approx.

• Discussed the role.

• Ring oscillator.

• Setup time and hold time.

• What is STA?

• Binary search algorithm, pseudocode, and time complexity.

• Negative feedback op-amp.

• Summing circuit using an op-amp and what happens if we interchange the inverting and non-inverting terminals.

• Suppose there are two FFs having the same clock; will the clock reach exactly at the same time? If not, why, and how can it be reduced?

• Clock skew, clock uncertainty, and clock jitter.

• 2-FF synchronizer.

• What are cache lines?

• What are dirty lines and the dirty bit?

• What is a watchdog timer?

• What is cache memory, and what is its need and importance?

• Difference between SRAM and DRAM.

• Why is SRAM used in cache?

• Verilog code for an AND gate using a MUX.

• Is Stack LIFO or FIFO?

• Is SRAM volatile or non-volatile, and why?

• Aptitude Question 1: There are 100 gates and 100 people. All gates are initially closed. The 1st person will flip the 1st, 2nd, 3rd... up to the 100th gate. The 2nd person will flip the 2nd, 4th, 6th... up to the 100th gate. The 3rd person will flip the 3rd, 6th, 9th... up to the 99th gate, and so on, until the 100th person. After all 100 people do this, how many gates will be open? (Flip means closing if open and opening if closed).

  • Answer: floor(sqrt(N)), where N is the total number of people. The logic is that the r-th gate will be open at the end if r is a perfect square.

• Aptitude Question 2: In a cube-shaped room with side 'a', there is an ant at one corner. It cannot fly, obviously, and it can move on the floor, the walls, etc. What is the minimum distance it has to travel to reach the diagonally opposite corner of the cube?

  • Answer: sqrt(5) * a
  • Hint given: Unfold the cube into a 2D plane, then you can see the shortest path.

HR Round - 5-10 minutes

• Asked about myself, my skills, hobbies, family, and strengths.
• Preferred job location.

What are setup time and hold time?