EX-803-C VLSI Circuits and Systems - May 2023 Question Paper

Under each question, How to answer lists the points an answer should cover, outlined by CampusPrep from the syllabus. Check the details against your textbook.

1. 7 Marks
   aExplain the electrical properties of MOS transistor in detail.
   How to answer

   • Definition of MOS transistor structure and terminal voltages
   • I-V characteristics in cutoff, linear and saturation regions
   • Threshold voltage, body effect and channel-length modulation
   • Capacitances, transconductance and small-signal parameters
2. 7 Marks
   bExplain the need of scaling, scaling principles and fundamental units of CMOS inverter.
   How to answer

   • Need for scaling in VLSI density, speed and power
   • Constant-field vs constant-voltage scaling principles
   • Scaling effects on dimensions, voltage and doping
   • Fundamental units / operation of CMOS inverter
3. 7 Marks
   aWrite the layout design rules and Draw the layout diagram for NAND and NOR gate.
   How to answer

   • Lambda-based layout design rules for wires, contacts and transistors
   • Spacing, width and overlap rules
   • CMOS NAND layout construction
   • CMOS NOR layout construction with diagram
4. 7 Marks
   bDraw and explain any of the combinational circuit using CMOS and verify their result with the help of suitable truth tables.
   How to answer

   • CMOS combinational circuit structure with pull-up and pull-down networks
   • Circuit diagram for selected gate / logic
   • Operation for input combinations
   • Truth table verification of result
5. 7 Marks
   aWhat is Elmore's Constant? Give Elmore delay expression for propagation delay of an inverter.
   How to answer

   • Definition of Elmore delay constant
   • RC tree model assumptions
   • Elmore delay expression for propagation delay
   • Application to inverter chain
6. 7 Marks
   bWhat is Transmission gate? Explain the use of transmission gate.
   How to answer

   • Construction of transmission gate using NMOS and PMOS in parallel
   • Control signals and switching behavior
   • Advantages over single pass transistor
   • Applications as switch, mux and latch
7. 7 Marks
   aExplain the methodology of sequential circuit design of latches and flip-flops.
   How to answer

   • Difference between latches and flip-flops
   • Steps in sequential circuit design methodology
   • Clocking, setup-hold and state assignment
   • Example latch / flip-flop realization
8. 7 Marks
   bExplain the operation of master slave based edge triggered register.
   How to answer

   • Master-slave configuration using two latches
   • Clock and inverted clock operation phases
   • Edge-triggered data capture mechanism
   • Timing diagram for register operation
9. 7 Marks
   aExplain clock distribution techniques in synchronous design in detail.
   How to answer

   • Need for clock distribution in synchronous design
   • H-tree, grid and spine distribution techniques
   • Skew and jitter minimization
   • Buffering and clock gating considerations
10. 7 Marks
    bExplain the concept of carry look ahead adder with neat diagram
    How to answer

    • Generate and propagate concept for carry look ahead
    • Carry equations and look-ahead logic
    • Block diagram of CLA adder
    • Speed advantage over ripple carry adder
11. 7 Marks
    aExplain the structure of booth multiplier with a suitable example.
    How to answer

    • Booth recoding principle for multiplication
    • Structure of Booth multiplier datapath
    • Worked example with suitable operands
    • Advantages for signed multiplication
12. 7 Marks
    bDesign 16 bit carry bypass adder and discuss their features.
    How to answer

    • Partition of 16-bit adder into bypass blocks
    • Bypass multiplexer and carry logic
    • Block diagram of 16-bit carry bypass adder
    • Speed, area and power features
13. 7 Marks
    aDiscuss different types of programming technology used in FPGA design.
    How to answer

    • Role of configuration memory in FPGA
    • Antifuse, SRAM, EPROM/EEPROM and Flash technologies
    • Comparison of volatility and reprogrammability
    • Suitability for FPGA design
14. 7 Marks
    bExplain about building block architecture of FPGA.
    How to answer

    • Configurable logic blocks (CLBs)
    • Interconnect and switch matrices
    • I/O blocks and routing resources
    • Overall FPGA building-block architecture diagram
15. 14 Marks
    Write a short note on any two:

    1. a)Stick Diagram
    2. b)Pass Transistor Logic
    3. c)Pipelines
    4. d)Cell Libraries
    How to answer

    • Brief definition and purpose of selected topics
    • Key construction / working principle with diagram
    • Advantages, limitations and applications