Are you preparing for a SystemVerilog interview in 2025? Whether you’re a VLSI fresher, verification engineer, or seasoned ASIC design professional, this comprehensive list of the top 75 SystemVerilog interview questions and answers will help you master everything from basic syntax to advanced verification concepts.

SystemVerilog is a widely adopted hardware verification and design language used in building complex SoCs. Companies expect candidates to be proficient in areas like OOP, constrained random verification, assertions, interfaces, coverage, and testbench automation. With real-world examples and detailed explanations, this guide is your one-stop solution to crack interviews confidently.

1. What is SystemVerilog?

Answer:
SystemVerilog is a hardware description and verification language (HDVL) that extends Verilog with advanced features for design, testbenches, and functional verification.

2. What are the major enhancements of SystemVerilog over Verilog?

Answer:

• Object-oriented programming (OOP)
  
  
• Constrained random verification
  
  
• Functional coverage
  
  
• Interfaces
  
  
• Assertions (SVA)
  
  
• New data types (logic, bit, enum, struct)
  
  

3. What is the difference between bit, logic, and reg?

4. What is an interface in SystemVerilog?

Answer:
An interface bundles signals into a single unit to simplify module connections.

Example:

interface bus_if;

  logic clk;

  logic rst;

  logic [7:0] data;

endinterface

5. What are the different types of covergroups?

Answer:
Covergroups are used to measure functional coverage.

• coverpoint
  
  
• cross
  
  
• bins
  
  

6. What is the difference between shallow copy and deep copy in SystemVerilog?

Answer:

• Shallow copy: Copies only object reference.
  
  
• Deep copy: Creates a new copy of all fields, including nested objects.
  
  

7. What is a virtual interface?

Answer:
A pointer to a physical interface used in classes to separate testbench and DUT.

Example:

virtual bus_if vif;

8. What are the constraints in SystemVerilog?

Answer:
Used to generate valid random values for class properties.

Example:

constraint c { a > 5; a < 10; }

9. What is the difference between rand and randc?

Answer:

• rand: Random value without repetition guarantee.
  
  
• randc: Cyclic randomization; avoids repeats until all values are used.
  
  

10. What is functional coverage?

Answer:
Checks whether all intended functional scenarios are exercised during simulation.

11. What is a mailbox in SystemVerilog?

Answer:
A communication mechanism between processes (producer-consumer).

mailbox mbx;

mbx.put(data); // Producer

mbx.get(data); // Consumer

12. What is a semaphore?

Answer:
Used for resource sharing across processes.

13. Explain initial vs always block.

• initial: Executes only once at time 0.
  
  
• always: Executes repeatedly when trigger conditions are met.
  
  

14. What is an event in SystemVerilog?

Answer:
Used to synchronize between processes.

15. What are the types of inheritance in SystemVerilog?

• Single inheritance
  
  
• Multilevel inheritance (no multiple inheritance allowed)
  
  

16. What is the difference between static and automatic tasks/functions?

17. What is the difference between task and function?

18. What is DPI (Direct Programming Interface)?

Answer:
Allows SystemVerilog to call C/C++ functions and vice versa.

19. What are assertions in SystemVerilog?

Answer:
Used to verify properties (temporal expressions) in simulations.

Types:

• Immediate
  
  
• Concurrent
  
  

20. Give an example of an immediate assertion.

assert (a == b) else $error(“Mismatch”);

21. What is a transaction in SystemVerilog?

Answer:
A class object representing data exchanged between testbench and DUT.

22. What is polymorphism?

Answer:
Using a parent class handle to refer to subclass objects.

23. What is the factory pattern in UVM/SystemVerilog?

Answer:
Used to create objects without changing code at instantiation sites.

24. What is a coverpoint?

Answer:
A single condition or variable you want to measure for coverage.

25. What is cross coverage and its purpose?

Answer:
Checks the combination of values between two or more coverpoints.

26. What is randomize()?

Answer:
A method to randomize class variables based on constraints.

27. What are the phases in SystemVerilog testbench (non-UVM)?

• Build phase
  
  
• Run phase
  
  
• Check phase
  
  
• Report phase
  
  

28. What is a parameterized class?

Answer:

class Packet #(int WIDTH=8);

  logic [WIDTH-1:0] data;

endclass

29. What is the purpose of typedef?

Answer:
Creates new type aliases for readability and reuse.

30. What is casting in SystemVerilog?

Answer:
Type conversion between compatible data types using $cast().

31. What are typedef enum and typedef struct?

Used to define user-defined data types for grouping related constants/fields.

32. What are queues and how are they different from arrays?

Answer:

• Arrays: Fixed-size
  
  
• Queues: Dynamic and ordered (int q[$];)
  
  

33. What is a dynamic array?

Answer:
Size can be allocated at runtime using new[].

34. What is the difference between ref, input, and output?

• input: Read-only
  
  
• output: Write-only
  
  
• ref: Read-write access
  
  

35. What is the $display, $monitor, and $strobe difference?

• $display: Immediate
  
  
• $monitor: Continuous monitoring
  
  
• $strobe: Executes at end of time step
  
  

36. What is the role of fork-join in parallel process execution?

Answer:
Runs multiple processes concurrently.

37. How do you use randomization with constraints inside a class?

class Data;

  rand int a;

  constraint a_range { a > 10; a < 20; }

endclass

38. What is the significance of super keywords?

Answer:
Refers to the parent class from the child class method.

39. How do you override virtual methods?

Use virtual in base class and override in child class.

40. What is this keyword?

Refers to the current instance of the class.

41. What are associative arrays in SystemVerilog?

Answer:
Arrays indexed by arbitrary data types (e.g., string).

int data[string];

42. What is process control like disable/kill in SystemVerilog?

SystemVerilog allows you to control and terminate processes using process handles.

43. What is a scoreboard in testbenches?

A verification component that compares expected vs actual output.

44. What is a monitor in SV testbench?

Captures signals from DUT and sends them to the scoreboard.

45. What is the difference between class and module?

• module: Hardware abstraction
  
  
• class: Testbench abstraction (OOP support)
  
  

46. What is the default data type in SystemVerilog?

• logic or bit instead of wire or reg.
  
  

47. What is simulation time unit in SV?

Set using timescale, e.g., timescale 1ns/1ps.

48. How do you import packages in SystemVerilog?

import my_pkg::*;

49. What is a unique and priority keyword in case statements?

Used to catch unhandled conditions and optimize synthesis.

50. What are classes, handles, and objects?

• Class: User-defined data type.
  
  
• Object: Instance of class.
  
  
• Handle: Pointer to an object.
  
  

51. What is the difference between randcase and case?

Answer:
randcase selects a case based on weighted probabilities; case is deterministic.

Example:

randcase

  3: a = 1;

  7: a = 0;

endcase

Here, a = 1 has a 30% chance, a = 0 has a 70% chance.

52. What is a constraint_mode() method?

Answer:
Enables or disables constraints dynamically.

Example:

obj.constraint_mode(0); // disables constraints

53. How do you disable a specific constraint in SystemVerilog?

Answer:

constraint my_c { a < 10; }

…

obj.my_c.constraint_mode(0); // disables the constraint

54. What is the use of foreach in SystemVerilog?

Answer:
Iterates over arrays and queues.

Example:

foreach(array[i])

  $display(“Value: %0d”, array[i]);

55. How can you implement a singleton class in SystemVerilog?

Answer:

class Singleton;

  static Singleton inst;

  static function Singleton get();

    if (inst == null)

      inst = new();

    return inst;

  endfunction

endclass

56. What is the randsequence construct?

Answer:
Generates random sequences using production rules.

Example:

randsequence (main)

  main : a b;

  a : { $display(“A”); };

  b : { $display(“B”); };

endsequence

57. What is the disable iff in assertions?

Answer:
Temporarily disables the assertion under a condition.

assert property (@(posedge clk) disable iff (reset) a |=> b);

58. What is an immediate vs. concurrent assertion?

• Immediate: Checked at one simulation time.
  
  
• Concurrent: Spans multiple cycles; temporal assertions.
  
  

59. What is first_match in coverpoints?

Answer:
Stops at the first matching bin, useful in overlapping bin ranges.

60. What is a wildcard case statement?

Answer:

wildcard case (value)

  4’b1x0x: $display(“Match”);

endcase

x values are treated as wildcards.

61. Explain unique0 in SystemVerilog.

Answer:
Ensures zero or one match in a case statement.

62. What is the difference between $urandom and $random?

• $random: 32-bit, signed, predictable seed.
  
  
• $urandom: 32-bit, unsigned, better randomness.
  
  

63. What is $fatal, $error, $warning, $info?

Answer:
Built-in system tasks for reporting simulation messages by severity.

64. What is the use of wait_order in SV?

Answer:
Used to enforce a specific order of events.

wait_order(a, b, c);

65. How do you define covergroup dynamically?

Answer:

covergroup cg(int size);

  coverpoint size;

endgroup

66. What is a procedural assignment?

Answer:
Assignment in always blocks (= or <=), controls simulation updates.

67. What are program blocks in SystemVerilog?

Answer:
Used to define testbenches, executes after modules.

program test;

  initial $display(“Hello”);

endprogram

68. What is the difference between int and integer?

• int: 32-bit signed (SystemVerilog).
  
  
• integer: 32-bit signed (Verilog legacy).
  
  

69. Can constraints apply on static variables?

Answer:
No. Constraints can only apply to rand or randc non-static variables.

70. What are dynamic casting and static casting?

• Dynamic: $cast(handle, value); – safe at runtime.
  
  
• Static: (type)'(value); – compile-time cast.
  
  

71. What is an associative array iterator?

foreach(my_arr[key])

  $display(“Key=%s Value=%0d”, key, my_arr[key]);

72. How to randomize only selected class variables?

Answer:

class A;

  rand int a, b;

endclass

obj.randomize() with { a > 5; }; // Only constraint on a

73. What is a wildcard bin?

Answer:
Allows X/Z matching in coverage.

74. How do you use constraint inheritance?

Answer:
Child class inherits constraints unless overridden.

75. What are wildcard and case equality operators?

• ==: Logical equality
  
  
• ===: Case equality (checks X/Z)
  
  
• !==: Case inequality
  
  
• ==?: Wildcard equality
  
  

Mastering SystemVerilog is essential for anyone aiming to build a career in VLSI design and verification. This guide featuring the top 75 SystemVerilog interview questions with examples provides you with a solid foundation in both basic and advanced concepts.

By practicing these questions regularly and understanding the logic behind each feature, you’ll not only prepare effectively for job interviews but also become a stronger verification engineer. Bookmark this resource and revisit it for ongoing learning, and stay tuned for upcoming posts on UVM, SV assertions, and FPGA-based interview preparation.