Lecture # 1
ENG6090
ENG 6090 – VLSI Design
– VLSI Design
Introduction to VLSI Design – Lec01. 1
ENG 6090 – VLSI Design
Professor: Shawki Areibi (Off:Thorn 2335) sareibi@uoguelph.ca
Lecture Mon - Fri
Laboratory
10:30 - 12:00 pm
Thorn2336
ENG 2307 (Digital Design Lab)
Course Web Page www.uoguelph.ca/~sareibi
Introduction to VLSI Design – Lec01. 2
ENG 6090 – VLSI Design
COURSE INFORMATION
Syllabus
Grading
Texts
- VLSI Design/Reconfigurable Computing
30% Assign
10% Presentation 40% Project 20% Exams
- Kang & Leblebici. “CMOS Digital Integrated Circuits”
- Rabaey. J. “Digital Integrated Circuits”, 2002
- Uyemura J. P. “Physical Design of CMOS Integrated
Circuits Using L-Edit” (optional reference)
Project
- Cadence Tools
- Technology Files (0.18 process)
Course Expectations
Introduction to VLSI Design – Lec01. 3
- Must Do a Project to Illustrate your Understanding
ENG 6090 – VLSI Design
ENG6090 – COURSE
OBJECTIVES
1. This course provides an introduction to the fundamental
principles of VLSI circuit design.
2. Emphasis is placed on the design of basic building blocks of
large scale digital integrated circuits and systems.
3. Understand the concept behind ASIC Design.
4. Implement a complete digital system on silicon using state of
the art CAD tools.
5. Understand the consequence of scaling down the dimensions
of transistors and its affect on device speed, density, ….
6. Have the necessary background to complete CMOS designs
and assess which particular design style to use on a given
design from FPGA to Full custom design.
Introduction to VLSI Design – Lec01. 4
ENG 6090 – VLSI Design
ENG6090 TOPICS TO BE
COVERED
Overview of VLSI Design Cycle and Methodologies
nMOS, pMOS transistor theory and design equations
Overview of VLSI fabrication technology,
Basic CMOS digital circuits, transistor-level and mask-level design,
Complex logic gates, modular building blocks
Data path components, ASIC design guidelines,
Hardware Descriptive Languages
Reconfigurable Computing Systems (FPGAs)
Physical Design Automation
Introduction to VLSI Design – Lec01. 5
ENG 6090 – VLSI Design
VLSI:Very Large Scale Integration
• Integration: Integrated Circuits
– multiple devices on one substrate
• How large is Very Large?
• SSI (small scale integration)
– 7400 series, 10-100 transistors
• MSI (medium scale)
– 74000 series 100-1000
• LSI 1,000-10,000 transistors
• VLSI > 10,000 transistors
• ULSI/SLSI (some disagreement)
Introduction to VLSI Design – Lec01. 6
ENG 6090 – VLSI Design
WHY VLSI?
Integration Improves the Design
• Lower parasitics, higher clocking speed
• Lower power
• Physically small
Integration Reduces Manufacturing Costs
• (almost) no manual assembly
• About $1-5billion/fab
• Typical Fab 1 city block, a few hundred people
• Packaging is largest cost
• Testing is second largest cost
• For low volume ICs, Design Cost may swamp
all manufacturing cost
Introduction to VLSI Design – Lec01. 7
ENG 6090 – VLSI Design
Levels of Design
• Specifications
• IO, Goals and Objectives, Function, Costs
• Architectural Description
• VLHD, Verilog, Behavioral, Large Blocks
• Logic Design
• Gates plus Registers
• Circuit Design
• Transistors sized for power and speed
• Discrete Logic, Technology Mapping
• Layout
• Size, Interconnect, Parasitics
Introduction to VLSI Design – Lec01. 8
ENG 6090 – VLSI Design
SYSTEM
+
MODULE
GATE
CIRCUIT
G
S
n+
Introduction to VLSI Design – Lec01. 9
D
n+
DEVICE
ENG 6090 – VLSI Design
What is “CMOS VLSI”?
• MOS = Metal Oxide Semiconductor (This used to
mean a Metal gate over Oxide insulation)
• Now we use polycrystalline silicon which is
deposited on the surface of the chip as a gate. We
call this “poly” or just “red stuff” to distinguish it
from the body of the chip, the substrate, which is a
single crystal of silicon.
• We do use metal (aluminum) for interconnection
wires on the surface of the chip.
Introduction to VLSI Design – Lec01. 10
ENG 6090 – VLSI Design
D
S
G
D
G
S
Poly crossed over Diffusion
 Field effect transistor (FET)
Insulated Gate  Metal Oxide Semiconductor FET
Source and Drain are Interchangeable
Introduction to VLSI Design – Lec01. 11
ENG 6090 – VLSI Design
N-Channel Enhancement mode MOS FET
• Four Terminal Device - substrate bias
–The “self aligned gate” - key to CMOS
Introduction to VLSI Design – Lec01. 12
ENG 6090 – VLSI Design
CMOS:Complementary MOS
• Means we are using both N-channel and P-channel
type enhancement mode Field Effect Transistors
(FETs).
• Field Effect- NO current from the controlling
electrode into the output
– FET is a voltage controlled current device
– BJT is a current controlled current device
• N/P Channel - doping of the substrate for increased
carriers (electrons or holes)
Introduction to VLSI Design – Lec01. 13
ENG 6090 – VLSI Design
Complementary Metal Oxide
Semiconductor
VDD
PMOS
X’
X
NMOS
VSS
Introduction to VLSI Design – Lec01. 14
ENG 6090 – VLSI Design
Four Views
Logic
Transistor
Introduction to VLSI Design – Lec01. 15
Layout
Physical
ENG 6090 – VLSI Design
VLSI Design
• The real issue inVLSI is about designing systems on
chips.
• The designs are complex, and we need to use
structured design techniques and sophisticated
design tools to manage the complexity of the design.
• We also accept the fact that any technology we learn
the details of will be out of date soon.
• We are trying to develop and use techniques that
will transcend the technology, but still respect it.
Introduction to VLSI Design – Lec01. 16
ENG 6090 – VLSI Design
Help from Computer Aided Design tools
• Tools
–
–
–
–
–
–
–
Editors
Simulators
Libraries
Module Synthesis
Place/Route
Chip Assemblers
Silicon Compilers
Introduction to VLSI Design – Lec01. 17
• Experts
– Logic design
– Electronic/circuit
design
– Device physics
– Artwork
– Applications - system
design
– Architectures
ENG 6090 – VLSI Design
Design Styles
•
•
•
•
•
•
Full custom
Standard cell
Gate-array
Macro-cell
“FPGA”
Combinations
Introduction to VLSI Design – Lec01. 18
ENG 6090 – VLSI Design
Full Custom
•
•
•
•
•
•
•
Hand drawn geometry
All layers customized
Digital and analog
Simulation at transistor level (analog)
High density
High performance
Long design time
Introduction to VLSI Design – Lec01. 19
ENG 6090 – VLSI Design
Full Custom
Vdd
IN
Out
Gnd
Introduction to VLSI Design – Lec01. 20
ENG 6090 – VLSI Design
Standard cells
• Standard cells organized in rows (and, or, flipflops,etc.)
• Cells made as full custom by vendor (not user).
• All layers customized
• Digital with possibility of special analog cells.
• Simulation at gate level (digital)
• Medium density
• Medium-high performance
• Reasonable design time
Introduction to VLSI Design – Lec01. 21
ENG 6090 – VLSI Design
Standard cells
Routing
Cell
IO cell
Introduction to VLSI Design – Lec01. 22
ENG 6090 – VLSI Design
Gate-array
• Predefined transistors connected via metal
• Two types: Channel based
Channel less (sea of gates)
• Only metallization layers customized
• Fixed array sizes (normally 5-10 different)
• Digital cells in library (and, or, flip-flops,etc.)
• Simulation at gate level (digital)
• Medium density
• Medium performance
• Reasonable design time
Introduction to VLSI Design – Lec01. 23
ENG 6090 – VLSI Design
Gate-array
Sea of gates
Channel based
Vdd
NAND gate using gate isolation
Vdd
A
B
PMOS
B
Oxide isolation
Out
A
Out
NMOS
Gate isolation
Gnd
Can in principle be used by adjacent cell
Gnd
Introduction to VLSI Design – Lec01. 24
ENG 6090 – VLSI Design
Gate-array
Sea of gates
RAM
Introduction to VLSI Design – Lec01. 25
ENG 6090 – VLSI Design
Macro cell
•
•
•
•
•
•
•
•
•
•
Predefined macro blocks (Processors, RAM,etc)
Macro blocks made as full custom by vendor
All layers customized
Digital and some analog (ADC)
Simulation at behavioral or gate level (digital)
High density
DSP processor
High performance
LCD
RAM
Short design time
cont.
Use standard on-chip busses
ADC
ROM
“System on a chip”
Introduction to VLSI Design – Lec01. 26
ENG 6090 – VLSI Design
FPGA = Field Programmable Gate Array
•
•
•
•
•
•
•
•
•
•
Programmable logic blocks
Programmable connections between logic blocks
No layers customized (standard devices)
Digital only
Low - medium performance (<50 - 100MHz)
Low - medium density (up to ~100k gates)
Programmable by: SRAM, EEROM, Anti_fuse, etc
Cheap design tools on PC’s
Low development cost
High device cost
Introduction to VLSI Design – Lec01. 27
ENG 6090 – VLSI Design
FPGA
Introduction to VLSI Design – Lec01. 28
ENG 6090 – VLSI Design
Comparison
FPGA
Density
Flexibility
Analog
Performance
Design time
Design costs
Tools
Volume
Low
Low (high)
No
Low
Low
Low
Simple
Low
Gate array
Medium
Low
No
Medium
Medium
Medium
Complex
Medium
Introduction to VLSI Design – Lec01. 29
Standard cell
Full custom
Medium
High
Medium
High
No
Yes
High
Very high
Medium
High
Medium
High
Complex
Very complex
High
High
Macro cell
High
Medium
Yes
Very high
Medium
High
Complex
High
ENG 6090 – VLSI Design
High performance devices
• Mixture of full custom, standard cells and macro’s
• Full custom for special blocks: Adder (data path),
etc.
• Macro’s for standard blocks: RAM, ROM, etc.
• Standard cells for non critical digital blocks
Introduction to VLSI Design – Lec01. 30
ENG 6090 – VLSI Design
ASIC with mixture of full custom,RAM and standard cells
Single port RAM
Dual port RAM
Full custom
Standard cell
FIFO
Introduction to VLSI Design – Lec01. 31
ENG 6090 – VLSI Design
Pentium
Introduction to VLSI Design – Lec01. 32
ENG 6090 – VLSI Design
ALPHA & MOTOROLA POWER PC
Alpha
Introduction to VLSI Design – Lec01. 33
ENG 6090 – VLSI Design
New combinations
• FPGA’s with RAM, PCI interface, Processor, ADC, etc.
• Gate arrays with RAM, Processor, ADC, etc
Processor
FPGA or Gate-array logic
RAM
Introduction to VLSI Design – Lec01. 34