THIRD B.TECH ECE STUDENTS

1. Unit-v
vlsi design process
prepared by
B.S.NageswaraRao
Assistant Professor
Eswar College of Engineering
Narasaraopet

2.  SEQUENCE OF STEPS REQUIRED FOR VLSI DESIGNS TO
DESIGN A CHIP WITH CONSTRAINTS.
 SIZE
 AREA
 POWER AND DELAY IS CALLED DESIGN PROCESS

3.  The Process Of Designing Of Vlsi Circuit Is Highly
Complex Task
 Complexity Increases, Design Flow And
Verification Become Tedious
 CAD tool are used to ease the process of design
flow by using automation process

4.  Process For Developing A Chip From Concept To
Silicon Divided Into Four Steps
 DESIGN
 VERIFICATION
 IMPLIMENTATION
 SOFTWARE DEVELOPMENT

5.  DESIGN:IT IS START WITH DESCRIPTION OF
SPECIFICATIONS OF THE SYSTEM TO BE DESIGN
 DESCRIPTION OF THE DESIGN CAN TAKES PLACE
ANY ONE OF THE FALLOWING
 A)BEHAVIORAL DOMINE:
 IT SPECIFY THE HARDWARE IMPLIMENTATION OF
THE SYSTEM’S FUNCTIONALITY WITH HELP OF
SEQUENCE OF REGISTER TRANSFER STATEMENTS

6. b)STRUCTURAL DOMINE
 DESIGN DESCRIBE WITH SET OF SUB MODULES
CONNECTED TOGETHER TO FUNCTION

7. c)PHYSICAL DOMINE
 It Specify The Layout Used To Build The System
According To Architect Idea At The Transistor
Level

8. VERIFICATION
To verify the functionality of a chip that is
to be performed according to
specifications
It is an important step to designing a
reliable designs
Verification is at different levels
A)register transfer level(high level of
abstraction)
B)transistor level(low level of abstraction)

9. implimentation
 After verification required design realized
onto the hardw
 physical implementation of the required
function with actual hardware components
that result entity or product
 It include both logic and physical
implementation

10. software
 This is last task process of program the
brain of the chip for desire function

11. TECHNOLOGY OPTIONS
 DIFFERENT OPTIONS FOR CREATING PHYSICAL
REALIZATION OF DIGITAL CIRCUIT ONTO SILICON
CHIP
 TWO OPTIONS TO FABRICATE THE CHIP FROM THE
CIRCUIT LEVEL TO THE PHYSICAL REALIZATION
 FULL CUSTOM
 SEMI-CUSTOM

12. FULL- CUSTOM DESIGN
 DESIGNER HANDLEXIBILITY CHOOSE LODIC,
CRAFT ALL DIGITAL CIRCUITS,THIS IS EARLY
DAYS OF DEGITAL DESIGN
 FUNCTION AND LAYOUT OF EVERY
TRASISTOR CUSTOMIZE AND OPTIMIZE BY
DESIGNER
 INTEL 4004 PROCESSOR IS EXAMPLE

13.  ADVANTAGES:
 HIGH FERFORMANCE
 MINIMUM AREA MAXIMUM SPEED
 DIS-ADV:
 REQUIRE MORE MAN POWER
 HIGH COST AND LONG TIME TO MARKET
 DESIGN COST IS HIGH
 LONG TIME FOR VERIFICATION

14. SEMI-CUSTOM
CLASSIFIED AS
1)CELL BASED DESIGN
2)ARRAY BASED DESIGN

15. CELL BASED DESIGN
CLASSIFIED AS
1)STANDARD CELL DESIGN
2)MACRO CELL
3)COMPILED CELL

16. ARRAY BASED DESIGN
 1)PRE-DIFFUSED DESIGN
 2)PRE-WIRED DESIGN

17. CELL BASED DESIGN
 LOGIC ELEMENT IMPLIMENTED BY CIRCUIT CONSIST
OF ONE OR MORE PRIMITIVE GATES(AND,OR,NOT).
 UNIVERSAL GATES(NAND,NOR)
 XOR,XNOR
 SEQUENTIAL ELEMENTS(FF’S)
 COMPLEX FUNCTION(AND-OR-INVERT)
 MUX’S,FULL
ADDER,COMPARATOR,COUNTER,DECODER AND
ENCODER
 THOSE ARE REUSABLE

18. DUE TO REUSE
 REDUCT TIME TO MARKET
 CHALLENGE IN THIS IS SELECTION CELLS
AND COMBINE THEM FOR REQUIRE
FUNCTION

19. ADVANTAGES OF CELL BASED DESIGN
 MINIMIZE DESIGN EFFORT TIME DUE TO
REUSABLE PROPERTY
 PRE-DESIGNED CELLS REDUCE THE
COMPLEXITY OF THE CIRCUIT

20. DIS-ADVANTAGES OF CELL BASED DESIGN
 FIXED LOGIC ELEMENTS IN LIBRARY
 IT REDUCES THE POSSIBILITY OF 100
PERCENTAGE DESIGNERS CHOICE BASED ON
OBJECTIVES
 FAN-OUT AND FAN-IN ARE NOT KNOWN IN
ADVANCE

21. STANDARD CELL-BASED DESIGN
 LOGIC CELL ARE PLACED IN ROWS THAT ARE
SEPERATED BY INTERCONNECT CHANNELS
 Cells are different sizes
 Cells in rows are same height but different
widths
 Interconnection is overhead

22. Compiled cell based design
 Designer have choice to customize and
optimize the cells
 Cells are generated by software tools as
function of user supplied parameters
 Cells are placed based on predefined
technology rules
 Such as cell size,power budget,routing
style.

23. Macro cell based design
 Cells are pre designed
 Muxs
 Datapaths
 Memories
 Dsp and embedded processors
 Functionality androuting with in the module is
fixed or flexible

24. Array-based designs
 Pre-diffused: primitive cells or transistors are
manufactured by the vendors
 All the fabrication steps needed to make these primitive
cells are standard and optimized irrespective of
application
 Desired inter connections and only few metallization steps
 Example: masked fpga

25. Pre-wired: in this manufacturing is
separated from implementation
It performed at user's site
Example:fpga

26. Power calculations
