EE40: Introduction to

Microelectronic
Circuits
Summer 2006
Octavian Florescu
florescu@eecs

First Week Announcements

n Class web page will be up today.
http://inst.eecs.berkeley.edu/~ee40/ will have
class syllabus, staff, office hours, schedule,
exam, grading , etc. info
n Text (Hambley, “Electrical Engineering:
Principles and Applications”, 3rd ed.) covers
most of class material. Reader will be available
later in the semester for digital IC and fabrication
subjects
n Lectures to be available on web, day before
each class. Please print a copy if you wish to
have it in class.
EE40 Summer 2006: Lecture 1 Instructor: Octavian Florescu 2

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Announcements cont’d
n Sections begin this week
¨ Cancelled section: Th 12-2.
n Labs begin this week. Attend your only second
lab slot this week.
¨ Cancelled labs: ThF 2-5.
¨ 8 Labs and 2 Project Labs.
n Weekly homeworks
¨ Assignment on web on Monday. Due following
Monday in hw box at 6pm.
¨ 1st Homework online today and next Monday. Sorry!
n 2 Midterms
¨ Tentatively on 07/11 and 07/27.

EE40 Summer 2006: Lecture 1 Instructor: Octavian Florescu 3

Announcements cont’d
n My Office Hours
¨ M,W,F 11-12 in Cory 382
¨ Or just e-mail me at florescu@eecs

n TAs:
¨ Lab TA: Mary Knox, knoxm@eecs
¨ Discussion TA: Micheal Krishnan, mnk@berkeley
¨ Reader: Bill Hung, billhung@berkeley

n TA Office Hours
¨ TBD

EE40 Summer 2006: Lecture 1 Instructor: Octavian Florescu 4

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 Lecture 1

n Course overview
n Introduction: integrated circuits
n Energy and Information
n Analog vs. digital signals
n Circuit Analysis

EE40 Summer 2006: Lecture 1 Instructor: Octavian Florescu 5

EE40: Course Overview

n EECS 40:
¨ One of five EECS core courses (with 20, 61A,
61B, and 61C)
n introduces “hardware” side of EECS
n prerequisite for EE105, EE130, EE140, EE141
¨ Prerequisites: Math 1B, Physics 7B
n Course content:
¨ Electriccircuits
¨ Integrated-circuit devices and technology
¨ CMOS digital integrated circuits

EE40 Summer 2006: Lecture 1 Instructor: Octavian Florescu 6

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Course Overview Cont’d
n Circuit components
¨ Resistor, Dependent sources, Operational amplifier
n Circuit Analysis
¨ Node, Loop/Mesh, Equivalent circuits
¨ First order circuit

n Active devices
¨ CMOS transistor
n Digital Circuits
¨ Logic gates, Boolean algebra
¨ Gates design

EE40 Summer 2006: Lecture 1 Instructor: Octavian Florescu 7

What is an Integrated Circuit?

P4 2.4 Ghz, 1.5V, 131mm2 300mm wafer, 90nm

n Designed to performs one or several functions.

n Composed of up to 100s of Millions of transistors.

EE40 Summer 2006: Lecture 1 Instructor: Octavian Florescu 8

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Transistor in Integrated Circuits
90nm transistor (Intel)

n Transistors are the workhorse of modern ICs

¨ Used to manipulate signals and transmit energy
¨ Can process analog and digital signals

EE40 Summer 2006: Lecture 1 Instructor: Octavian Florescu 9

Benefit of Transistor Scaling

Generation: 1.5µ 1.0µ 0.8µ 0.6µ 0.35µ 0.25µ

Intel386™ DX
Processor smaller chip area à lower cost

Intel486™ DX
Processor

Pentium®
Processor

Pentium® II
more functionality on a chip
Processor
à better system performance

EE40 Summer 2006: Lecture 1 Instructor: Octavian Florescu 10

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Technology Scaling: Moore’s Law
Technology
Scaling

Lower Cost
Investment Per Function

Market
Growth

n 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

EE40 Summer 2006: Lecture 1 Instructor: Octavian Florescu 11

Some Applications

n Computers
n Communication Devices
n Automotive sensors/actuators
n Biotechnology

EE40 Summer 2006: Lecture 1 Instructor: Octavian Florescu 12

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Energy and Signals in an IC
n Electrical circuits function to condition,
manipulate, transmit, receive electrical
power (energy) and/or information
represented by electrical signals
n Energy System Examples: electrical utility
system, power supplies that interface
battery to charger and cell phone/laptop
circuitry, electric motor controller, ….
n Information System Examples: computer,
cell phone, appliance controller, …..

EE40 Summer 2006: Lecture 1 Instructor: Octavian Florescu 13

Signals in Integrated Circuits:

Analog and Digital
f(t)
g(z)

110, 001, 100, 000, 011, 111…

t

n Analog n Digital
¨ May represent a physical ¨ Array of discrete words
phenomenon directly ¨ z in g(z) is integer and
¨ Continuous in time indexes one discrete word
¨ f(t) is a real scalar of the array

EE40 Summer 2006: Lecture 1 Instructor: Octavian Florescu 14

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 Digital Representation
g(z) g(t)

3V

2V
1V
110, 001, 100, 000, 011, 111…
0V
-1 V t
-2 V
-3 V
110 001 100 000 011 111 Digital Word

n Each digital word can be represented by a

discrete amplitude
n Can be a quantization of an analog signal
n g(t) takes on discrete, quantized values

EE40 Summer 2006: Lecture 1 Instructor: Octavian Florescu 15

Analog vs. Digital Signals

f(t) g(t)
3V

2V
1V

t
VS 0V
t
-1 V

-2 V
-3 V 011 111 Digital Word
110 001 100 000

n Most (but not all) observables are analog.

n The most convenient/efficient way to represent, transmit and
manipulate information electronically is to use digital signals.
n Analog-to-digital (A/D) & digital-to-analog (D/A) conversion is
essential and nothing new; think sheet music converted to song.

EE40 Summer 2006: Lecture 1 Instructor: Octavian Florescu 16

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Typical Microelectronic System:
Audio System

Digital Signal D/A

A/D
Processing

Analog Digital Analog

Domain Domain Domain

EE40 Summer 2006: Lecture 1 Instructor: Octavian Florescu 17

Introduction to circuit analysis

OUTLINE
n Electrical quantities
¨ Charge
¨ Current
¨ Voltage
¨ Power

n The ideal basic circuit element

n Sign conventions

Reading
Chapter 1

EE40 Summer 2006: Lecture 1 Instructor: Octavian Florescu 18

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 Circuit Analysis
n 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

n 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 2006: Lecture 1 Instructor: Octavian Florescu 19

Electric Charge
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 à electric force (voltage)
§ charges in motion à electric flow (current)
EE40 Summer 2006: Lecture 1 Instructor: Octavian Florescu 20

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Classification of Materials
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 ×1022 free electrons per cubic cm)
Electrons in semiconductors are not tightly bound and
can be easily “promoted” to a free state.
insulators semiconductors metals

Quartz, SiO2 Si, GaAs Al, Cu

dielectric materials excellent conductors

EE40 Summer 2006: Lecture 1 Instructor: Octavian Florescu 21

Electric Current
Definition: rate of positive charge flow
Symbol: i
Units: Coulombs per second Amperes (A)
i = dq/dt
where q = charge (in Coulombs), t = time (in seconds)

Note: Current has polarity.

EE40 Summer 2006: Lecture 1 Instructor: Octavian Florescu 22

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Electric Current Examples
1. 105 positively charged particles (each with charge
1.6×10-19 C) flow to the right (+x direction) every
nanosecond.
Q 1 05 ´1 .1 6´ 19 0-
I = = + -9 = ´ 1 . 6 1 -05 A
t 1 0

2. 105 electrons flow to the right (+x direction) every 15

microseconds.

EE40 Summer 2006: Lecture 1 Instructor: Octavian Florescu 23

Current Density
Definition: rate of positive charge flow per unit area
Symbol: J
Units: A / cm2
Example 1: Semiconductor with 1018 “free
electrons” per cm3
Wire attached
to end
2 cm

10 cm

Suppose we force a current of 1 A to flow from C1 to C2:

• Electron flow is in -x direction:
1C / sec electrons
= -6.25 ´1018
- 1.6 ´10 -19 C / electron sec
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Current Density Example (cont’d)
What is the current density in the semiconductor?

Example 2:
Typical dimensions of integrated circuit components are
in the range of 1 mm. What is the current density in a wire
with 1 mm² area carrying 5 mA?

EE40 Summer 2006: Lecture 1 Instructor: Octavian Florescu 25

Electric Potential (Voltage)

n Definition: energy per unit charge
n Symbol: v
n 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.
a Subscript convention:
vab means the potential at a
minus the potential at b.
b vab va - vb

EE40 Summer 2006: Lecture 1 Instructor: Octavian Florescu 26

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Electric Power
n Definition: transfer of energy per unit time
n Symbol: p
n Units: Joules per second Watts (W)

p = dw/dt = (dw/dq)(dq/dt) = vi

n 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 2006: Lecture 1 Instructor: Octavian Florescu 27

The Ideal Basic Circuit Element

i
• Polarity reference for voltage is
+ indicated by plus and minus signs
v
• Reference direction for the current
_
is indicated by an arrow

Attributes:
n Two terminals (points of connection)
n Mathematically described in terms of current
and/or voltage
n Cannot be subdivided into other elements

EE40 Summer 2006: Lecture 1 Instructor: Octavian Florescu 28

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A Note about Reference Directions
A problem like “Find the current” or “Find the voltage”
is always accompanied by a definition of the direction:

i - v +

In this case, if the current turns out to be 1 mA flowing

to the left, we would say i = -1 mA.
In order to perform circuit analysis to determine the
voltages and currents in an electric circuit, you need to
specify reference directions. There is no need to guess
the reference direction so that the answers come out
positive, however.
EE40 Summer 2006: Lecture 1 Instructor: Octavian Florescu 29

Sign Convention Example

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

a
measuring v ab.
-1.401 The DVM indicates -1.401, so
DVM v a is lower than v b by 1.401 V.

b + Which is the positive battery

terminal?

Note that we have used the “ground” symbol ( ) for the reference
node on the DVM. Often it is labeled “C” for “common.”

EE40 Summer 2006: Lecture 1 Instructor: Octavian Florescu 30

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Sign Convention for Power
Passive sign convention

p = vi p = -vi
i i i i
_ _
+ +
v v v v
_ + _ +

n If p > 0, power is being delivered to the box.

n If p < 0, power is being extracted from the box.
EE40 Summer 2006: Lecture 1 Instructor: Octavian Florescu 31

Power
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:
i i
_
+
v or v
_ +

How can a circuit element absorb power?

By converting electrical energy into heat (resistors in toasters),
light (light bulbs), or acoustic energy (speakers); by storing
energy (charging a battery).
EE40 Summer 2006: Lecture 1 Instructor: Octavian Florescu 32

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Power Calculation Example
Find the power absorbed by each element:
Conservation of energy
è total power delivered
equals
total power absorbed
Aside: For electronics these are unrealistically
large currents – milliamperes or smaller is more
typical
vi (W) p (W)
918
- 810
- 12
- 400
- 224
1116

EE40 Summer 2006: Lecture 1 Instructor: Octavian Florescu 33

Summary
n Current = rate of charge flow
n Voltage = energy per unit charge created by
charge separation
n Power = energy per unit time
n Ideal Basic Circuit Element
¨ 2-terminal component that cannot be sub-divided
¨ described mathematically in terms of its terminal
voltage and current
n Passive sign convention
¨ Reference direction for current through the element is
in the direction of the reference voltage drop across
the element
EE40 Summer 2006: Lecture 1 Instructor: Octavian Florescu 34

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