Systems with Digital Integrated Circuits
Transcript of Systems with Digital Integrated Circuits
Introduction
Sorin Hintea
Basis of Electronics Departament
Systems with Digital Integrated Circuits
Systems with digital integrated circuits - Introduction 2
Commutative logic
The operation of digital circuits is based on the use of switches capable of going through two
distinct states and opposite each other
Ideal switches have zero resistance in ON and infinite in OFF state
In digital circuits are used, electronic switches made with MOS transistors
These transistors are real circuit elements whose ON and OFF resistors are finite
Conductive resistance other than 0 will cause the output response to be delayed
The finite value resistance in the locked state will result in a final drain current through the
blocked switch and therefore undesired power dissipation
Cut-offVG = GND
conductionVG = VDD
MO
S
tran
sist
or ‘0’
‘1’
Systems with digital integrated circuits - Introduction 3
Proiectarea CID – nivele de abstractizare
Real Circuits Response
vout
vin C
R
tp = ln (2) t = 0.69 RC
Time behavior of digital circuit’s output
Logic switches in real digital integrated circuits are built with MOS transistors
which have an ON resistance of about10 kohms and OFF resistance of about 100
Mohms.
These values are far from the ideal ones and cause power losses and delays of signal
propagation through the circuits
Systems with digital integrated circuits - Introduction 4
Ideal and real digital circuits
Behaviour of real digital circuits
Blue - ideal input signal; Black –real output signal
0 0.5 1 1.5 2 2.5
x 10-10
-0.5
0
0.5
1
1.5
2
2.5
3
t (sec)
Vo
ut(V
)
tp = 0.69 CL (Reqn+Reqp)/2
Time behavior of digital circuit’s output
Systems with digital integrated circuits - Introduction 5
Ideal and real digital circuits
Delay in signals propagation - effect of circuit non idealities
Vout
tf
tpHL tpLH
tr
t
V in
t
90%
10%
50%
50%
Systems with digital integrated circuits - Introduction 6
Digital Circuits Design
First digital integrated circuits
1947 – making the first transistor in the Bell Telephone labs
1949 – first bipolar transistor by Schockley
1958 – first integrated CMOS circuit
1962 – first integrated TTL family circuit (Transistor-
Transistor Logic)
1972 – first 4 bits microprocessor 4004 made by INTEL
Systems with digital integrated circuits - Introduction 7
Digital Circuits Design
First digital integrated circuits
� In the 1970s, mostly nMOS processes were used, cheaper but with high power
consumption
� From the 1980s to today, more and more CMOS processes are being used for their reduced power consumption
[Vadasz69]
© 1969 IEEE.
Intel Museum.
Reprinted with permission.
Systems with digital integrated circuits - Introduction 8
The Moore’s law
In 1965, Gordon
Moore noted that the
number of transistors on a
chip doubled every 18 to
24 months.
So he predicted that
semiconductor
technology will evolve to
double the number of
transistors every 18
months, which is still true
today
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Electronics, April 19, 1965.
Systems with digital integrated circuits - Introduction 9
Digital Circuits Evolution
The evolution of the number of chip transistors by 2010
1,000,000
100,000
10,000
1,000
10
100
1
1975 1980 1985 1990 1995 2000 2005 2010
8086
80286i386
i486Pentium®
Pentium® Pro
K1 Billion
Transistors
Source: Intel
Projected
Pentium® II
Pentium® III
Dupa Rabaey, 2005
Systems with digital integrated circuits - Introduction 10
Digital Circuits Evolution
The evolution of the number of chip transistors by 2010 in
microprocessors industry
Rabaey, 2005
40048008
80808085 8086
286386
486Pentium® proc
P6
0.001
0.01
0.1
1
10
100
1000
1970 1980 1990 2000 2010
Year
Tra
ns
isto
rs (
MT
)
2X growth in 1.96 years!
Transistors on Lead Microprocessors double every 2 years
Systems with digital integrated circuits - Introduction 11
Digital Circuits Evolution
Evolution of microprocessors working frequency by 2010
Rabaey, 2005
P6
Pentium ® proc486
38628680868085
8080
80084004
0.1
1
10
100
1000
10000
1970 1980 1990 2000 2010
Year
Fre
qu
en
cy (
Mh
z)
Lead Microprocessors frequency doubles every 2 years
Doubles every2 years
Systems with digital integrated circuits - Introduction 12
Digital Circuits Evolution
Increasing Microprocessors power dissipation until 2000
Rabaey, 2005
P6Pentium ® proc
486
386
2868086
80858080
80084004
0.1
1
10
100
1971 1974 1978 1985 1992 2000
Year
Po
we
r (W
att
s)
Lead Microprocessors power continues to increase
Systems with digital integrated circuits - Introduction 13
Digital Circuits Evolution
Power consumption will increases to unmanageable values
Rabaey, 2005
5KW 18KW
1.5KW
500W
40048008
80808085
8086286
386486
Pentium® proc
0.1
1
10
100
1000
10000
100000
1971 1974 1978 1985 1992 2000 2004 2008
Year
Po
we
r (W
att
s)
Power delivery and dissipation will be prohibitive
Systems with digital integrated circuits - Introduction 14
Digital Circuits Evolution
Intel Pentium Processor (IV)
Systems with digital integrated circuits - Introduction 15
Digital Circuits Evolution
Evaluating the results of a digital circuit design
Systems with digital integrated circuits - Introduction 16
CMOS technology
How to implement digital integrated circuits :
Single die
Wafer
Going up to 12” (30cm)
Systems with digital integrated circuits - Introduction 17
Digital Circuits Evolution
Some examples of digital integrated circuit parameters :
Chip Metal layers
Line width
Wafer cost
Def./ cm2
Area mm2
Dies/wafer
Yield Die cost
386DX 2 0.90 $900 1.0 43 360 71% $4
486 DX2 3 0.80 $1200 1.0 81 181 54% $12
Power PC 601
4 0.80 $1700 1.3 121 115 28% $53
HP PA 7100 3 0.80 $1300 1.0 196 66 27% $73
DEC Alpha 3 0.70 $1500 1.2 234 53 19% $149
Super Sparc 3 0.70 $1700 1.6 256 48 13% $272
Pentium 3 0.80 $1500 1.5 296 40 9% $417
Systems with digital integrated circuits - Introduction 18
Digital Circuits Design
Principal design goals
• The design of a CID must follow the highest speed but also the power
consumed
• This is alongside occupying a smaller surface than the implemented circuit
• As a measure of the quality of the switching circuits, the product of the
delay time and the power consumed, a parameter called power-delay
product (PDP)
• In general pentru o anumita tehnologie si o topologie data, PDP este
constant
• In the case of CMOS circuits if the propagation time is to decrease, the
transistors are resized by increasing the width of the channel;
• n this way, the surface of the transistor increases, which leads to the increase
of the current and the power consumed, keeping the PDP constant
Power-Delay Product (PDP) = E = Energy per operation = Pav tp
Systems with digital integrated circuits - Introduction 19
Digital Circuits Design
Evaluating the results of a digital circuit design
Major targets:
� Working speed (delay time, working frequency)
� Power disipation
� Occupied area by a specified circuit
Secondary targets
� Cost
� Reliability
� Scalability
� The energy required to achieve a function
Systems with digital integrated circuits - Introduction 20
Digital Circuits Design
Design abstraction levels in digital circuits
n+n+
S
GD
+
DEVICE
CIRCUIT
GATE
MODULE
SYSTEM
Systems with digital integrated circuits - Introduction 21
Digital Circuits Design
In ce directie evolueaza proiectarea circuitelor digitale VLSI
The technology evolves in the sense of decreasing the size by 0.7 / generation
With each generation you can integrate 2 times more features on the chip; the cost of the chip does not increase significantly
Cost per feature is down 2 times
This has as a consequence a growing number of functions that must be projected by a growing number of human designers
This requires a more efficient design method
Such a method is to increase abstraction levels as well as scalability
Passing from one generation to another is done by applying a constant of all dimensions in the old project