vlsi interview questions: 36 VLSI Interview Questions (With Sample Responses)


Answer ( 1 )


    vlsi interview questions: 36 VLSI Interview Questions (With Sample Responses)


    I’m assuming that you are looking for a job as a VLSI circuit designer. Well, I can help! The following questions will test your knowledge of a variety of VLSI design topics, including computer-aided design (CAD), logic synthesis and verification, physical layout, and packaging.

    Is VLSI a part of electronics?

    The word “VLSI” stands for “very large scale integration,” which is a type of integrated circuit. VLSI is not a part of electronics and it does not refer to the size of an electronic device like your TV or phone.

    In fact, VLSI is actually used in many different fields such as computer engineering, electrical engineering and computer science.

    What is the difference between digital and analog design?

    Digital design is based on binary logic. Analog design is based on continuous signals. Digital circuits perform calculations, while analog circuits process signals. This means that digital designs are faster than their analog counterparts; but they also require more transistors to do the same job!

    What is an advantage of using CMOS vs NMOS technology?

    • CMOS is more energy efficient:
    • CMOS is cheaper to manufacture:
    • CMOS is faster in terms of clock speed:
    • CMOS is more reliable:
    • CMOS is more versatile:

    What are the commonly used VLSI design tools?

    • EDA tools
    • Simulation tools
    • Layout tools
    • Synthesis tools
    • Verification tools
    • Test tools

    What are the most common types of VLSI circuits?

    There are many different types of VLSI circuits. They can be classified into five main categories: sequential circuits, combinational circuits, memory circuits, logic circuits and digital analog-to-digital converters (ADCs).

    Sequential Circuits

    The most common type of circuit is the sequential one. In this type of circuit the output depends on some input conditions that have already occurred in previous clock periods before it was processed. For example a counter will count from 0 to n before resetting back to 0 again; this kind of system is called a “state machine”. Combinational logic has been used since 1950s when transistors were first invented but only recently with advances in technology have they become more powerful than their predecessors which were made up entirely using discrete components such as resistors and capacitors etc…

    What are some common physical limitations to VLSI technology?

    Electromigration is a physical phenomenon in which the mobility of charge carriers in a metal conductor causes gradual change in its structure. This can lead to device failure due to short circuits, open circuits and reliability issues.

    Diffusion capacitance is defined as the amount of charge stored at each node during one clock cycle due to diffusion current flow into or out of the node (i.e., capacitance between two adjacent nodes). This can cause unwanted delay in signal transmission through interconnects when there are multiple paths between two nodes due to its effect on resistance values along those paths; this problem is known as “signal skew”.

    Transition time refers to how long it takes for a transistor’s output voltage level (V) changes from logic low value (-0.8V) until logic high value (+2V) after receiving input pulse (I), which depends on several factors including supply voltage Vdd(5V), load resistance RL(1kOhm), input capacitance Cin(5pF). The maximum allowable transition time is limited by process technology limits such as gate oxide thicknesses etc., thus making it necessary for designers using CMOS processes today not only consider how much power they want their design consume but also how fast each function needs perform before making decisions regarding whether it makes sense at all

    Which of these VLSI design constraints influence each other? Design time, test time, and yield.

    The following are some of the most common design constraints that influence each other:

    • Design time and test time. These two factors are closely related because a longer design cycle will require more testing, which can increase costs and lower your yield.
    • Yield. This is another important factor to consider when designing VLSI systems–it’s one thing if you’re building something for yourself or an elite clientele, but if your goal is to make money off mass production (and why else would someone be working at this level?), then you need a high-yield product so that each manufactured unit works as intended without fail.

    Explain the difference between CDV (constant delay) and CDF (constant delay factor). Give examples where one or the other might be used.

    The difference between CDV and CDF is that the former is the number of delay elements divided by the number of inputs, while the latter is that same number minus one.

    For example:

    • In a pipelined processor design with two registers and eight stages, what would be your choice for delay?
    • How much longer does it take an instruction to complete if you have an extra register stage?
    • How would you optimize this design if you were given some additional resources (e.g., more transistors)?

    It takes a lot of knowledge to make small circuits.

    VLSI design is a complex process that requires knowledge of physics, electrical engineering, and computer science. You must also know about the technology you are using (e.g., CMOS transistors) and how to use it well. Finally, if your designs are going to be manufactured in volume by an outside company–or if they’re just going to be used as prototypes–you need to know what kind of tools are available for this purpose.


    If you want to get into VLSI design, you’ll need to know your stuff. It’s not enough just to know about the different types of circuits and how they work; you also need to know how each one affects other aspects of the process like yield and test time. This is why we put together this guide full of 36 questions we think every candidate should be prepared for! We hope it helps

Leave an answer