Interview Questions:

  • Have you studied buses? What types?
  • Have you studied pipelining? List the 5 stages of a 5 stage pipeline. Assuming 1 clock per stage, what is the latency of an instruction in a 5 stage machine? What is the throughput of this machine ?
  • How many bit combinations are there in a byte?
  • For a single computer processor computer system, what is the purpose of a processor cache and describe its operation?
  • Explain the operation considering a two processor computer system with a cache for each processor.
  • What are the main issues associated with multiprocessor caches and how might you solve them?
  • Explain the difference between write through and write back cache.
  • Are you familiar with the term MESI?
  • Are you familiar with the term snooping?
  • Describe a finite state machine that will detect three consecutive coin tosses (of one coin) that results in heads.
  • In what cases do you need to double clock a signal before presenting it to a synchronous state machine?
  • You have a driver that drives a long signal & connects to an input device. At the input device there is either overshoot, undershoot or signal threshold violations, what can be done to correct this problem?
  • What are the total number of lines written by you in C/C++? What is the most complicated/valuable program written in C/C++?
  • What compiler was used?
  • What is the difference between = and == in C?
  • Are you familiar with VHDL and/or Verilog?
  • What types of CMOS memories have you designed? What were their size? Speed?
  • What work have you done on full chip Clock and Power distribution? What process technology and budgets were used?
  • What types of I/O have you designed? What were their size? Speed? Configuration? Voltage requirements?
  • Process technology? What package was used and how did you model the package/system? What parasitic effects were considered?
  • What types of high speed CMOS circuits have you designed?
  • What transistor level design tools are you proficient with? What types of designs were they used on?
  • What products have you designed which have entered high volume production?
  • What was your role in the silicon evaluation/product ramp? What tools did you use?
  • If not into production, how far did you follow the design and why did not you see it into production?

Source

  • Insights of an inverter. Explain the working?Insights of a 2 input NOR gate. Explain the working?Insights of a 2 input NAND gate.
  • Explain the working?Implement F= not (AB+CD) using CMOS gates?Insights of a pass gate. Explain the working?
  • Why do we need both PMOS and NMOS transistors to implement a pass gate?
  • What does the above code synthesize to?
  • Cross section of a PMOS transistor?
  • Cross section of an NMOS transistor?
  • What is a D-latch? Write the VHDL Code for it?
  • Differences between D-Latch and D flip-flop?
  • Implement D flip-flop with a couple of latches? Write a VHDL Code for a D flip-flop?
  • What is latchup? Explain the methods used to prevent it?
  • What is charge sharing?
  • While using logic design, explain the various steps that r followed to obtain the desirable design in a well defined manner?
  • Why is OOPS called OOPS? (C++)
  • What is a linked list? Explain the 2 fields in a linked list?
  • Implement a 2 I/P and gate using Tran gates?
  • Insights of a 4bit adder/Sub Circuit?
  • For f = AB+CD if B is S-a-1, what r the test vectors needed to detect the fault?
  • Explain various adders and diff between them?
  • Explain the working of 4-bit Up/down Counter?
  • A circuit has 1 input X and 2 outputs A and B. If X = HIGH for 4 clock ticks, A = 1. If X = LOW for 4 clock ticks, B = 1. Draw a state diagram for this Spec?
  • Advantages and disadvantages of Mealy and Moore?
  • Id vs. Vds Characteristics of NMOS and PMOS transistors?
  • Explain the operation of a 6T-SRAM cell?
  • Differences between DRAM and SRAM?
  • Implement a function with both ratioed and domino logic and merits and demerits of each logic?
  • Given a circuit and asked to tell the output voltages of that circuit?
  • How can you construct both PMOS and NMOS on a single substrate?
  • What happens when the gate oxide is very thin?
  • What is setup time and hold time?
  • Write a pseudo code for sorting the numbers in an array?
  • What is pipelining and how can we increase throughput using pipelining?
  • Explain about stuck at fault models, scan design, BIST and IDDQ testing?
  • What is SPICE?
  • Differences between IRSIM and SPICE?
  • Differences between netlist of HSPICE and Spectre?
  • What is FPGA?
  • Draw the Cross Section of an Inverter? Clearly show all the connections between M1 and poly, M1 and diffusion layers etc?
  • Draw the Layout of an Inverter?
  • If the current thru the poly is 20nA and the contact can take a max current of 10nA how would u overcome the problem?
  • Implement F = AB+C using CMOS gates?
  • Working of a 2-stage OPAMP?
  • 6-T XOR gate?
  • Differences between blocking and Non-blocking statements in Verilog?
  • Differences between Signals and Variables in VHDL? If the same code is written using Signals and Variables what does it synthesize to?
  • Differences between functions and Procedures in VHDL?
  • What is component binding?
  • What is polymorphism? (C++)
  • What is hot electron effect?
  • Define threshold voltage?
  • Factors affecting Power Consumption on a chip?
  • Explain Clock Skew?
  • Why do we use a Clock tree?
  • Explain the various Capacitances associated with a transistor and which one of them is the most prominent?
  • Explain the Various steps in Synthesis?
  • Explain ASIC Design Flow?
  • Explain Custom Design Flow?
  • Why is Extraction performed?
  • What is LVS, DRC?
  • Who provides the DRC rules?
  • What is validation?
  • What is Cross Talk?
  • Different ways of implementing a comparator?
  • What r the phenomenon which come into play when the devices are scaled to the sub-micron lengths?
  • What is clock feed through?
  • Implement an Inverter using a single transistor?
  • What is Fowler-Nordheim Tunneling?
  • Insights of a Tri-state inverter?
  • If an/ap = 0.5, an/ap = 1, an/ap = 3, for 3 inverters draw the transfer characteristics?
  • Differences between Array and Booth Multipliers?
  • Explain the concept of a Clock Divider Circuit? Write a VHDL code for the same?
  • Which gate is normally preferred while implementing circuits using CMOS logic, NAND or NOR? Why?
  • Insights of a Tri-State Inverter?
  • Basic Stuff related to Perl?
  • Have you studied buses? What types?
  • Have you studied pipelining? List the 5 stages of a 5 stage pipeline. Assuming 1 clock per stage, what is the latency of an instruction in a 5 stage machine? What is the throughput of this machine ?
  • How many bit combinations are there in a byte?
  • For a single computer processor computer system, what is the purpose of a processor cache and describe its operation?
  • Explain the operation considering a two processor computer system with a cache for each processor.
  • What are the main issues associated with multiprocessor caches and how might you solve them?
  • Explain the difference between write through and write back cache.
  • Are you familiar with the term MESI?
  • Are you familiar with the term snooping?
  • Describe a finite state machine that will detect three consecutive coin tosses (of one coin) that results in heads.
  • In what cases do you need to double clock a signal before presenting it to a synchronous state machine?
  • You have a driver that drives a long signal & connects to an input device. At the input device there is either overshoot, undershoot or signal threshold violations, what can be done to correct this problem?
  • What are the total number of lines written by you in C/C++? What is the most complicated/valuable program written in C/C++?
  • What compiler was used?
  • What is the difference between = and == in C?
  • Are you familiar with VHDL and/or Verilog?
  • What types of CMOS memories have you designed? What were their size? Speed?
  • What work have you done on full chip Clock and Power distribution? What process technology and budgets were used?
  • What types of I/O have you designed? What were their size? Speed? Configuration? Voltage requirements?
  • Process technology? What package was used and how did you model the package/system? What parasitic effects were considered?
  • What types of high speed CMOS circuits have you designed?
  • What transistor level design tools are you proficient with? What types of designs were they used on?
  • What products have you designed which have entered high volume production?
  • What was your role in the silicon evaluation/product ramp? What tools did you use?
  • If not into production, how far did you follow the design and why did not you see it into production?

Source