Cracking Analog Devices: Placement Diaries
Analog Devices is a world leader in the design, manufacture, and marketing of a broad portfolio of high-performance analog, mixed-signal, and digital signal processing (DSP) integrated circuits (ICs) used in virtually all types of electronic equipment. It is one of the top recruiters visiting NIT Rourkela for campus placements annually. This academic year (2020-21), four students, Hamvir Dev and Bibhupad Tripathy from B.Tech and Ayusna Subudhi and P Santosh Kumar Patra from the Dual Degree program, got recruited at Analog Devices Inc.
Team Monday Morning caught up with the recruits to get insights into their journey to success in this edition of Placement Diaries.
Bibhupad Tripathy (B.Tech, Department of Electronics and Communication)
Analog Devices was a much-awaited semiconductor company in the placement season 2020-21. When the Online test and personal interview dates were declared, I started brushing up on all the fundamentals of basic electronics and computer sciences. As the job title explains, we needed to have a thorough knowledge of operating systems, OOPS, microprocessors, signal systems, and digital electronics. I cleared all my nuances of C and C++ programming. MATLAB and Python prowess is a plus.
- OOPS from geeks for geeks
- C++, OOPS, interview questions from CPPNUTS (youtube).
- Signal systems, digital signal processing, and digital electronics fundamentals
- Operating systems from gate smashers (youtube)
- Puzzles and Bit manipulation questions from geeks for geeks.
It had 40 questions of both MCQ and Subjective type. Questions were mainly based on Aptitude, Microprocessors, Digital Electronics, Signal Systems, DSP, OOPS, C / C++ code snippets, concepts relating to paging, etc. I managed to score 21 out of 40 by mostly attempting questions on aptitude, C++, OOPS, microprocessor, and Digital Electronics.
Interview 1: They enquired about my favourite subject and my strong and weak subjects. I didn’t score well in the electronics part in the OT, so they chose to start with my weak area. They also made me solve those questions which I couldn’t attempt or answered wrong in the OT. Here are some of the questions asked during the first round-
- Make full adder only using half adders (OR gate not allowed)
- 4-1 mux using 2-1 mux
- Question-Related to Paging
- Question on interrupts.
- Data-address multiplexing
It was an hour-long interview. The interviewers spent 40 minutes asking questions from the topics I referred to as my weak points (core concepts- digital electronics, microprocessors, signals and systems, DSP). For the remainder of the interview, my strong subjects were the area of focus (C++, OOPS).
I answered 15 questions correctly in a duration of 20 mins (questions were mainly based on c++ outputs, run time polymorphism, object slicing, debugging code, big-endian, and little-endian ). They also gave me some questions to find output based on debugging and the OOPS concept like friend function, virtual function.
Interview 2: It Started with a discussion related to my Project, owing to which I explained Leukemia Cell Detection. The following questions were asked based on the same.
- Which CNN model used?
- What accuracy?
- What is SVM?
- Bias vs Variance?
- How do you compute variance in ML?
- What is ROC?
- What are dense layers?
- What is a softmax layer?
- How do you determine if the model is overfitting or underfitting?
- What is rbf kernel in svm?
They checked my GitHub link from my CV to find out about the projects I did. Do Ensure that GitHub has all the projects. The other key questions asked during the round were.
- Implement a 2D convolution of N*N image in C programming and then extend it to 3D convolution.
- Reverse a linked list in groups.
- Questions on the topic of the doubly Linked list.
- What are linear and non-linear data structures?
- Linear- array, linked list;
- Non- Linear – Graph, trees. This was followed by a question on the time complexities of trees.
- FIR vs IIR filter
- Questions on Flip flop conversion.
- Which has more latency: pre-increment or post-increment?
- Write the transfer function of an FIR filter from a given diagram.
- Code the reader-writer problem. The way they put up the question was real-world application, but it could be inferred as a reader-writer problem.
The following questions were asked in the third round-
- Types of the system: linear & non- Linear, static and dynamic, Casual & non-causal, stable and unstable, time-variant and time-invariant, LTI system. They gave 5 signal equations and asked to find out which type of system it was.
- Finding transfer function of a given equation. Draw the graphs.
- Design digital system from a given state diagram.
- An array was given. Asked me to write a program to encode the signal.
- Write macro “REPLACE(A, B)” to replace the 2nd byte of an unsigned integer A with the 3rd byte from another unsigned integer B. 0th byte is the rightmost byte.
- Aptitude question: water – milk mixture.
- How is function overloading implemented by the compiler? (Name mangling)
- What is the difference between the error handling methods of Java and C?
There were also a few questions related to my gesture recognition project.
It was with the software director of Analog Devices Inc. He pointed out my weak areas, asked me to focus on them, and asked me about projects. It was just like a normal discussion. He asked me about the placements scenario of our college. It was more of an interaction than an interview.
- Describe your job role for which you have applied.
- How are you fit for this job profile? (You have to convince them that this profile is exactly what you wanted. I had worked on VLSI, embedded systems, machine learning. I was good at coding. OS and OOPS were my strong areas.)
- What are your plans?
They want long term commitment from the selected candidates
Message to the Aspirants
Don’t panic and give up. Be optimistic in problem-solving.They will try to push you out of your comfort zone to see how you approach questions.You have no room to make mistakes in the answers to the question from your “strong area”.If you are stuck in a question, ask for hints. They will judge how you act upon those hints.
Hamvir Dev (B.Tech, Department of Electrical Engineering)
For coding questions, I practised from GeeksforGeeks and Codechef. For data structure, I followed the book by Narashima Karumanchi, and for Embedded System, I had watched the videos of Bharat Acharya.
Online Test (OT)
In OT, questions were basically from embedded systems, coding, electronics, and aptitude. In coding, questions were asked to find the error in a particular piece of code or find the result of a code. In Embedded Systems, I was asked some questions regarding 8085 coding, whereas some basic Digital and Analog concepts were asked in electronics. There were also some subjective questions where we had to write the solution.
There were three technical rounds post-OT. In the first technical round, I was asked questions on Digital and Analog electronics like flip flops, gates, OPAMP, etc. In the second technical round, I was given three coding questions and had to code in front of them. Then they asked a bit about Machine learning. In the third round, I was asked questions on data structures. All rounds were nearly an hour long.
I was asked about my background and weaknesses and in which subject I lagged in OT. I don’t think you need any preparations; you have to be confident enough about your answers and speak flawlessly.
Message to the Aspirants
I would advise you to be thorough in coding, especially the debugging part because most of the questions were to find the error. Then one must have good concepts on data structure as well as Embedded Systems (basically 8085). In aptitude and electronics, basic knowledge regarding the subject would suffice.
Ayusna Subudhi (Dual Degree, Department of Electronics and Communication)
As electronics is a vast domain, balancing each subject's theoretical and problem-solving aspects is crucial.
I went through almost all the subjects (Digital Electronics, Analog Electronics, Digital VLSI, Testing and Verification of VLSI circuits, Microcontroller and Microprocessor, Embedded systems, etc.) either by revising the notes (slides) or by watching relevant lecture videos.
Managing the time was quite challenging. So I made a list of essential topics (Static Timing analysis, FPGA, Serial protocols, ARM architecture, DFT concepts, FIFO, etc.) and distinguished the subjects and prepared accordingly.
- Digital Design by M. Morris Mano for digital electronics.
- CMOS digital integrated circuits by Sung-Mo Kang.
- Hardware Modelling Using Verilog by IIT Kharagpur NPTEL lectures.
- Analog electronics from Razavi electronics lectures by Long Kong.
- Puzzles from Geeks for Geeks.
- Static Timing Analysis from http://www.vlsi-expert.com/
To clear the OT, I used to practice a few problems after reading a particular topic. Considering the time constraints, I tried to focus more on quality rather than quantity of questions.
For ADI, as the process is quite different from other semiconductor companies, I used to practice Digital Electronics puzzles from various blogs and digital design problems.
Apart from these, I also practised aptitude, puzzles, and basic C++ programming (OOPS concept).
Conducting experiments during laboratory classes properly and understanding the underlying concepts and failure reasons also helped me.
There were three technical rounds.
1) In the first round of interviews, I was asked to solve questions from an online test and, apart from that, questions related to FIFO Depth, Static Timing Analysis, etc. A few questions were also asked related to my final year project.
2) In the second round, I was asked questions from every topic in VLSI Design, starting from the basics of digital electronics to the fabrication of CMOS. The interviewer was trying to find how strong my fundamentals are. There were several questions related to FPGA and its difference from ASIC. He also asked me a few puzzles.
3) I felt that the third technical round was the toughest one. The interviewer asked me about my projects and many questions regarding the alternate ways to optimize the architecture. There were questions related to finding hazards in a circuit, designing sequential circuits for a given series of numbers, and optimize the hardware associated with it, Static timing analysis, etc.
There were general questions regarding my interests, extracurricular activities, strengths, and weaknesses in the HR round.
Message to the Aspirants
The process may seem quite tedious, but patience and consistency is the key. Don't restrict yourself to books; go beyond them find various resources from the internet for several concepts. Focus more on the practical aspect because logical understanding is necessary as memorising things won't work consistently. Be enthusiastic about learning new things.
P Santosh Kumar Patra (Dual Degree, Department of Electrical Engineering)
Having strong fundamentals is essential, so I prepared in-depth on concepts of Digital Electronics, Analog Electronics, Digital Circuits, MOSFET, and Staggered Pin Grid Array (SPGA). Some theory courses in the M.Tech curriculum are based on Verilog and VHDL coding and its implementation in SPGA; these further enhanced my knowledge. I tried learning more about VLSI subjects, notably electronic design automation, through online courses by Prof. Indranil Sengupta. Apart from these, I also did a few other courses on Coursera, including “From Nand To Tetris,” which further gave me profound insights into the silicon industry.
In OT, there were around 14 multiple choice questions and 10 subjective questions based on the concepts of Digital Electronics, Analog Electronics, VLSI, and aptitude & reasoning. For subjective questions, due weightage was given to the approach to the solution.
There were 2 technical rounds each of 1 hour. The 1st technical round had questions based on the works mentioned in my CV, notably questions related to my project work.
In the 2nd technical interview, the interviewers reviewed the subjective answers of my OT. Questions that I could not answer in OT were taken up again, and the solution approach was carefully examined while they gave the hints and inputs in between.
While HR-related questions were asked in between the technical rounds, a dedicated HR round was conducted an hour past the 2nd technical round. The company sought an employee willing to stay and work with them for a long time. So I had to convince them that I was looking forward to working a long time.
Message to the Aspirants
Explore and learn more about the semiconductor industry. Have a good knowledge of your subjects, especially Digital and Analog Electronics. Develop your skillset. Build connections and grow your network using LinkedIn and other platforms, as this makes you aware of the recent developments and helps grab opportunities. Most importantly, be motivated and don’t feel dejected if you face early rejections. Try your best and keep on improving.
Team Monday Morning congratulates all the four achievers for their success and wishes them the very best for their future endeavours.