Download EE40 Summer 2005: Intro to Microelectronic Circuits - Lecture 1 by Octavian Florescu and more Study notes Physics in PDF only on Docsity!
EE40: Introduction to
Microelectronic
Circuits
Summer 2005
Octavian Florescu
florescu@eecs.berkeley.edu
EE40 Summer 2005: Lecture 1 Instructor: Octavian Florescu 2
First Week Announcements
Class web page
http://inst.eecs.berkeley.edu/~ee40/ will have
class syllabus, staff, office hours, schedule,
exam, grading , etc. info
Text (Hambley, “Electrical Engineering:
Principles and Applications”, 3 rd^ ed.) covers
most of class material. Reader will be available
later in the semester for digital IC and fabrication
subjects
Lectures to be available on web, day before
each class. Please print a copy if you wish to
have it in class.
EE40 Summer 2005: Lecture 1 Instructor: Octavian Florescu 3
Announcements cont’d
Sections begin this week
Cancelled Sections: Th 12-2. Labs begin this week. Attend your only second lab slot this week.
Cancelled labs: ThF 8-11, 2-5. Please check your Lab section.
8 Labs and 2 Project Labs. Weekly homeworks
Assignment on web on Thursday. Due following Thursday in hw box at 6pm.
1 st^ Homework online today and due Friday. Sorry! 2 Midterms in class.
Tentatively on 07/12 and 07/28.
EE40 Summer 2005: Lecture 1 Instructor: Octavian Florescu 4
Lecture 1
Course overview
Introduction: integrated circuits
Energy and Information
Analog vs. digital signals
Circuit Analysis
EE40 Summer 2005: Lecture 1 Instructor: Octavian Florescu 7
What is an Integrated Circuit?
P4 2.4 Ghz, 1.5V, 131mm^2 300mm wafer, 90nm
Designed to performs one or several functions. Composed of up to 100s of Millions of transistors.
EE40 Summer 2005: Lecture 1 Instructor: Octavian Florescu 8
Transistor in Integrated Circuits
Transistors are the workhorse of modern ICs
Used to manipulate signals and transmit energy
Can process analog and digital signals
90nm transistor (Intel)
EE40 Summer 2005: Lecture 1 Instructor: Octavian Florescu 9
Generation: Intel386™ DX Processor
Intel486™ DX Processor
Pentium® Processor
Pentium®^ II Processor
1.5μ 1.0μ 0.8μ 0.6μ 0.35μ 0.25μ
Benefit of Transistor Scaling
smaller chip area Æ lower cost
more functionality on a chip Æ better system performance
EE40 Summer 2005: Lecture 1 Instructor: Octavian Florescu 10
Technology Scaling: Moore’s Law
Number of transistors double every 18 months
Cost per device halves every 18 months
More transistors on the same area, more complex and powerful chips
Cost per function decreases
Technology Scaling
Investment
Lower Cost Per Function
Market Growth
EE40 Summer 2005: Lecture 1 Instructor: Octavian Florescu 13
Æ Analog-to-digital (A/D) & digital-to-analog (D/A) conversion is essential (and nothing new) think of a piano keyboard
- Most (but not all) observables are analog think of analog vs. digital watches
but the most convenient way to represent & transmit information electronically is to use digital signals think of telephony
Analog vs. Digital Signals
EE40 Summer 2005: Lecture 1 Instructor: Octavian Florescu 14
Analog Signals
May have direct relationship to information presented In simple cases, are waveforms of information vs. time In more complex cases, may have information modulated on a carrier, e.g. AM or FM radio A m p litu d e M o d u la te d S ig n a l
-
-0.
-0.
-0.
-0.
0
0.
0.
0.
0.
1
0 5 1 0 1 5 2 0 2 5 3 0 3 5 4 0 4 5 5 0
T im e in m ic ro s e c o n d s
Signal in microvolts
EE40 Summer 2005: Lecture 1 Instructor: Octavian Florescu 15
Digital Signal Representations
Binary numbers can be used to represent any quantity. We generally have to agree on some sort of “code”, and the dynamic range of the signal in order to know the form and the number of binary digits (“bits”) required.
Example 1: Voltage signal with maximum value 2 Volts
- Binary two ( 10 ) could represent a 2 Volt signal.
- To encode the signal to an accuracy of 1 part in 64 (1.5% precision), 6 binary digits (“bits”) are needed
Example 2: Sine wave signal of known frequency and maximum amplitude 50 μV; 1 μV “resolution” needed.
EE40 Summer 2005: Lecture 1 Instructor: Octavian Florescu 16
1100012 = 1x2^5 +1x2^4 +0x2^3 +0x2 2 + 0x2^1 + 1x2^0 = 32 10 + 16 10 + 1 10 = 49 10 = 4x10^1 + 9x10^0
Reminder About Binary and Decimal
Numbering Systems
EE40 Summer 2005: Lecture 1 Instructor: Octavian Florescu 19
Digital signals offer an easy way to perform logical functions, using Boolean algebra.
- Variables have two possible values: “true” or “false”
- usually represented by 1 and 0 , respectively. All modern control systems use this approach.
Example: Hot tub controller with the following algorithm
Turn on the heater if the temperature is less than desired (T < T (^) set ) and the motor is on and the key switch to activate the hot tub is closed. Suppose there is also a “test switch” which can be used to activate the heater.
Digital Representations of Logical Functions
EE40 Summer 2005: Lecture 1 Instructor: Octavian Florescu 20
- Series-connected switches: A = thermostatic switch B = relay, closed if motor is on C = key switch
- Test switch T used to bypass switches A, B, and C
Simple Schematic Diagram of Possible Circuit
110V (^) Heater
C B A
T
Hot Tub Controller Example
EE40 Summer 2005: Lecture 1 Instructor: Octavian Florescu 21
A B C T H 0 0 0 0 0 0 0 1 0 0 0 1 0 0 0 0 1 1 0 0 1 0 0 0 0 1 0 1 0 0 1 1 0 0 0 1 1 1 0 1 0 0 0 1 1 0 0 1 1 1 0 1 0 1 1 0 1 1 1 1 1 0 0 1 1 1 0 1 1 1 1 1 0 1 1 1 1 1 1 1
“Truth Table” for Hot Tub Controller
EE40 Summer 2005: Lecture 1 Instructor: Octavian Florescu 22
Basic logical functions: AND: “dot” Example: X = A · B OR: “+ sign” Example: Y = A+B NOT: “bar over symbol” Example: Z = A ¾ Any logical expression can be constructed using these basic logical functions
Additional logical functions: Inverted AND = NAND: Inverted OR = NOR: Exclusive OR:
Notation for Logical Expressions
AB (o n ly 0 when A and B = 1 ) A +B (only 1 whenA=B= 0 )
i.e.,A B A B
A B(only 1 whenA,Bdiffer)
⊕ except
EE40 Summer 2005: Lecture 1 Instructor: Octavian Florescu 25
Introduction to circuit analysis
OUTLINE
Electrical quantities
Charge
Current
Voltage
Power
The ideal basic circuit element
Sign conventions
Reading
Chapter 1
EE40 Summer 2005: Lecture 1 Instructor: Octavian Florescu 26
Circuit Analysis
Circuit analysis is used to predict the behavior
of the electric circuit, and plays a key role in
the design process.
Design process has analysis as fundamental 1st^ step
Comparison between desired behavior (specifications) and predicted behavior (from circuit analysis) leads to refinements in design
In order to analyze an electric circuit, we need
to know the behavior of each circuit element
(in terms of its voltage and current) AND the
constraints imposed by interconnecting the
various elements.
EE40 Summer 2005: Lecture 1 Instructor: Octavian Florescu 27
Macroscopically, most matter is electrically
neutral most of the time.
Exceptions: clouds in a thunderstorm, people on carpets in dry weather, plates of a charged capacitor, etc.
Microscopically, matter is full of electric charges.
- Electric charge exists in discrete quantities, integral multiples of the electronic charge -1.6 x 10-19^ coulombs
- Electrical effects are due to
separation of charge Æ electric force ( voltage )
charges in motion Æ electric flow ( current )
Electric Charge
EE40 Summer 2005: Lecture 1 Instructor: Octavian Florescu 28
Quartz, SiO (^2)
Solids in which all electrons are tightly bound to atoms
are insulators.
Solids in which the outermost atomic electrons are
free to move around are metals.
Metals typically have ~1 “free electron” per atom (~5 ×10 22 free electrons per cubic cm)
Electrons in semiconductors are not tightly bound and
can be easily “promoted” to a free state.
Classification of Materials
insulators semiconductors metals
Si, GaAs Al, Cu
dielectric materials excellent conductors
EE40 Summer 2005: Lecture 1 Instructor: Octavian Florescu 31
2 cm
10 cm
1 cm (^) C C X
Example 1:
Suppose we force a current of 1 A to flow from C1 to C2:
- Electron flow is in - x direction:
Current Density
sec
- 25 10
- 6 10 /
1 /sec 18 19
electrons C electron
C =− × − × −
Semiconductor with 10^18 “free Wire attached electrons” per cm^3 to end
Definition: rate of positive charge flow per unit area
Symbol: J
Units: A / cm^2
EE40 Summer 2005: Lecture 1 Instructor: Octavian Florescu 32
Example 2: Typical dimensions of integrated circuit components are in the range of 1 μm. What is the current density in a wire with 1 μm² area carrying 5 mA?
What is the current density in the semiconductor?
Current Density Example (cont’d)
EE40 Summer 2005: Lecture 1 Instructor: Octavian Florescu 33
Electric Potential (Voltage)
Definition: energy per unit charge
Symbol: v
Units: Joules/Coulomb ≡ Volts (V)
v = dw/dq
where w = energy (in Joules), q = charge (in Coulombs)
Note: Potential is always referenced to some point.
Subscript convention: v (^) ab means the potential at a minus the potential at b.
a
b v^ ab ≡^ v^ a - vb
EE40 Summer 2005: Lecture 1 Instructor: Octavian Florescu 34
Electric Power
Definition: transfer of energy per unit time
Symbol: p
Units: Joules per second ≡ Watts (W)
p = dw/dt = (dw/dq)(dq/dt) = vi
Concept:
As a positive charge q moves through a
drop in voltage v , it loses energy
energy change = qv
rate is proportional to # charges/sec
EE40 Summer 2005: Lecture 1 Instructor: Octavian Florescu 37
Suppose you have an unlabelled battery and you measure its voltage with a digital voltmeter (DVM). It will tell you the magnitude and sign of the voltage.
With this circuit, you are measuring v ab. The DVM indicates −1.401, so v a is lower than v b by 1.401 V.
Which is the positive battery terminal?
−1. DVM
a
b
Note that we have used the “ground” symbol ( ) for the reference node on the DVM. Often it is labeled “C” for “common.”
Sign Convention Example
EE40 Summer 2005: Lecture 1 Instructor: Octavian Florescu 38
Sign Convention for Power
If p > 0, power is being delivered to the box.
If p < 0, power is being extracted from the box.
v _
i
Passive sign convention
_
v
i
p = vi
v _
i _
v
i
p = - vi
EE40 Summer 2005: Lecture 1 Instructor: Octavian Florescu 39
If an element is absorbing power ( i.e. if p > 0), positive charge is flowing from higher potential to lower potential.
p = vi if the “passive sign convention” is used:
How can a circuit element absorb power?
Power
v _
i _
v
i
or
By converting electrical energy into heat (resistors in toasters), light (light bulbs), or acoustic energy (speakers); by storing energy (charging a battery).
EE40 Summer 2005: Lecture 1 Instructor: Octavian Florescu 40
Find the power absorbed by each element:
Power Calculation Example
vi (W) 918
- 810 **- 12
p (W)
Conservation of energy Î total power delivered equals total power absorbed Aside: For electronics these are unrealistically large currents – milliamperes or smaller is more typical
