6/21/2014
One person with a is equal to a force of 99 who have only . - John Stuart Mill, 1806-1873
Amplifiers
Amplifiers Fernando Victor V. de Vera ECE, M.Tech
AMPLIFIER General Presentation
• An electronic circuit which is capable of
increasing the signal magnitude or amplitude without appreciably altering the signal waveform characteristic. • AMPLIFICATION is the process of providing an increase in amplitude.
Classifications of Amplifiers
Classifications • • • • • • • •
Voltage Amplifier
Voltage Amplifier – Voltage-controlled voltage source Current Amplifier – Current-controlled current source Transconductance Amplifier – Voltage-controlled current source Transimpedance Amplifier – Current-controlled voltage source VoltageAmplifier
Current Amplifier
1
6/21/2014
Current Amplifier
Transconductance Amplifier
Transconductance Transconducta nce Amplifier
Transimpedance Transimpedance Amplifier
TransimpedanceAmplifier
AMPs Classifications - Summary
Summary
Types of Amplifiers • Amplifiers by Function • Amplifiers by Frequency Response
RQS – No. 3
Amplifiers by Function • VOLTAGE
• POWER
AMPLIFIER
AMPLIFIER
– The type of
– Type of amplifier
amplifier in which the output signal voltage is larger than the input signal voltage.
in which the output signal power is larger than the input signal power. The secret of success is constancy to purpose. Benjamin Disraeli
2
6/21/2014
Audio Amplifier
Amplifiers by Frequency Response
• Audio amplifiers are designed to amplify
signals with frequency between 15 Hz and 20 kHz. • Any amplifier that is designed for any band of frequencies contained in AUDIO RANGE is called Audio Amplifier.
• Audio Amplifier • RF Amplifier • Video Amplifier
RF Amplifier • RF Amplifiers are designed to amplify
signals with frequencies between 10 kHz and 100 GHz. • Any Amplifier designed to amplify frequency band included in the RF range is considered an RF Amplifier.
Video Amplifier AMPLIFIERS. • Also known as WIDEBAND AMPLIFIERS. • A Video Amplifier is designed to amplify a band of frequencies from 10 Hz to 6 MHz.
Question An audio amplifier operates in the
frequency range of
>>Bringing You Forward
POSSIBLE BOARD QUESTIONS
A. B. C. D.
0 to to 20 20 H Hzz 20 Hz to to 20 20 kHz kHz 20 to 200 200 kHz kHz Above Above 20 kHz
3
6/21/2014
Question
Which of the following refers to the gain
A tuned RF amplifier is
A. B. C. D.
Question of a circuit?
Narro Narrowb wband and Wide Wideba band nd Direct Direct coupled coupled Impedan Impedance ce coupled coupled
A. Input quantit quantity y of an amplifier amplifier divided by by the output quantity. B. The difference difference between between the input input voltage voltage and the output voltage of a circuit. C. The ratio ratio of the output output quantity quantity to to input quantity of an amplifier. D. The total increase increase in in output quality quality over over the input quantity of an amplifier.
Question Which of the following is a
transconductance amplifier? A. B. C. D.
OP-A OP-AMP MP BJT FET Vara Varact ctor or
Question Which of the following is a current
amplifier? A. B. C. D.
OP-A OP-AMP MP BJT FET Varac Varacto torr
Amplifier Classes • The class of operation of an amplifier is
determined by the amount of time – in relation to the input signal – that current flows in the circuit. >>Bringing YOU Forward
AMPLIFIER CLASSES
4
6/21/2014
Amplifier Classes • • • •
Class A Amplifiers
Class A Class B Class AB Class C
• The amount of the
output signal flow varies for full 360 degrees of the cycle. • Class A amplifier has a characteristic of GOOD FIDELITY and low EFFICIENCY.
Class A amplifier
Class A Amplifier
Class A - Grapical
Class B Amplifier
Class !
Class B Amplifier
• The amount of the
output signal flow is 180 degrees. • Class B amplifiers is twice as efficient as Class A amplifiers. • Class B amplifiers is used in cases where exactly 50% of the input signal is amplified. Class ! - Grapical
5
6/21/2014
Class B Amplifier
Class AB Amplifier • The output signal
flows for more than 180 degrees but less than 360 degrees. • Class AB amplifiers have better efficiency and poorer fidelity than Class A amplifiers.
Class A!
Class AB Amplifier
Class AB Amplifier
Class A! - Grapical
Class C Amplifier
Class C
Class C Amplifier
• Class C amplifier
operates on less than 50% of the input signal. • Class C amplifier has the BEST EFFICIENCY but WORST FIDELITY.
Class C - Grapical
6
6/21/2014
Class C Amplifier
Summary of Amplifier Classes
C"ASS#S of Amplifiers – Ta$le of Comparison
CLASSES of Amplifiers Comparison Class A
Class B
Class AB
Class C
Active region (linear portion)
Cut-off region
a little above cut-off
below cut-off
Conduction Angle
360O
180O
Between 180O – 35O
le!! t"an 180O
Distortion
low
"ig"
#o$erate
ver% "ig"
Maximum Efficiency
&5' 50' for tran!for#er couple$
8*5'
Between Cla!! B an$ A
#ore t"an 0'
Q-point position
>>Bringing You Forward
POSSIBLE BOARD QUESTIONS
RQS – No. %
Question A characteristic of an amplifier which
refers to how much of its supply power is delivered to the load. A. B. C. D.
Output Output RMS power power Output Output DC power power Effi Effici cienc ency y Clas Classs A
Question Which class of amplifier has the highest
linearity and least distortion? A. B. C. D.
Clas Classs A Class lass C Clas Classs AB Clas Classs B
7
6/21/2014
Question Which class of amplifier is
distinguished by the presence of output throughout the entire signal cycle and the input never goes into cutoff region? A. B. C. D.
Clas Classs A Class lass C Class lass B Clas Classs D
Question For maximum peak-to-peak output
voltage, the Q point should be A. B. C. D.
Near satura saturatio tion n Near Near cut cutof offf At the the center center of the dc dc load line At the center of the the ac load load line
Question Class C amplifiers are almost always
A. B. C. D.
Transformer-c Transformer-coupled oupled between between stages stages Operated Operated at at audio audio frequencies frequencies Tuned Tuned RF RF ampli amplifie fiers rs Wide Wideba band nd
Question With class A, the output
A. B. C. D.
Uncl Unclip ippe ped d Clipped Clipped on positive positive voltage voltage peak peak Clipped Clipped on negative negative voltage voltage peak peak Clipped Clipped on negative negative current current peak peak
Question The bandwidth of a class C
amplifier
decreases when the A. B. C. D.
Resonant Resonant frequen frequency cy increases increases Q incre increas ases es XL decr decreas eases es Load resistance resistance decreases decreases
signal should be
Question Complementary push-pull transistor
uses ___ transistors. A. B. C. D.
PNP PNP and and NPN NPN Darlington Darlington and feedback feedback pair Both Both NPN NPN FET FET and and BJT BJT
8
6/21/2014
Question Push-pull is almost always used with
A. B. C. D.
Question One advantage of a class B push-pull
amplifier is
Clas Classs A Class lass B Class lass C All of the the above above
A. B. C. D.
Other Amplifiers - Circuit Configurations output of • CASCADED AMPLIFIER – the output the first stage provides the input of the next stage (connected in a series fashion) • CASCODE AMPLIFIER – a commonemitter on the first stage feeding a common-base stage. This provides high input impedance and low noise.
&ter Amplifiers - Circuit Configurations
Very small small quiescent quiescent current drain Maximum Maximum efficienc efficiency y of 78.5 78.5 percent percent Greater Greater efficienc efficiency y than than class class A All of the the above above
Other Amplifiers - Circuit Configurations • DARLINGTON AMPLIFIER – two
transistors in which the collectors are tied together and the emitter of the first transistor is directly coupled to the base of the second transistor. The current gain β of this circuit is the product of the individual transistors’ current gain. Also called DARLINGTON PAIR, PAIR, DOUBLEEMITTER FOLLOWER, FOLLOWER, or β MULTIPLIER MULTIPLIER.. &ter Amplifiers - Circuit Configurations
Other Amplifiers - Circuit Configurations • DIFFERENTIAL AMPLIFIER – designed to
respond to the difference between the two input voltages. Differential amplifier is usually the input circuit of most lownoise power amplifiers and operational amplifiers.
>>Bringing YOU Forward
COUPLING
9
6/21/2014
Coupling • The process of transferring energy from
one circuit to another is called COUPLING.
Direct Coupling • The method of coupling with the least
number of circuit elements. • In direct coupling, the output of one stage is directly connected to the input of the following stage.
Direct Coupling
Types of Coupling • • • •
Direct Coupling RC Coupling Impedance Coupling Transformer Coupling
Direct Coupling • Direct Coupling provides a GOOD
FREQUENCY RESPONSE since no frequency-sensitive frequency-sensitive devices are present. • Disadvantages includes: – High Voltage requirement for the
succeeding stages, – It is difficult to match the impedance from stage to stage with direct coupling. – Not very efficient therefore losses increase as the number of stages increases.
RC Coupling • RC Coupling is the most used coupling in
amplifiers. • RC coupling allows the coupling of the signal while it isolates the biasing of each stage. • Disadvantage includes: LOW EFFICIENCY because of the resistor use dc power.
10
6/21/2014
RC Coupling
Impedance Coupling • Impedance Coupling is very similar to RC
coupling, the only difference is coil is used instead of resistor. • Impedance Coupling has better efficiency because of the small coil resistance used instead of a resistor in RC coupling.
Impedance Coupling
Transformer Coupling • In Transformer Coupling, inductors are
used in the primary and secondary therefore its more efficient. • Transformer Coupling Coupling is used for the final output because of the impedance matching qualities of the transformer.
Transformer Coupling
>>Bringing You Forward
POSSIBLE BOARD QUESTIONS
11
6/21/2014
Question A passive device used for
phase-splitting
of a signal. A. B. C. D.
Trans Transfo forme rmerr OP-A OP-AMP MP Voltage Voltage divider configurati configuration on All All of the these se
Questi on
If three amplifiers with a gain of 8 each
are in cascade, how much is the overall gain? A. B. C. D.
72 512 24 8
Question The current in a coupling circuit for high
frequencies is A. B. C. D.
Question A coupling capacitor is ___.
A. B. C. D.
Zero Maxi Maximu mum m Mini Minimu mum m Aver Averag age e
A dc dc sho short rt An ac open open A dc open open and and an ac short short A dc short and an ac open open
Question A disadvantage of transformer coupling,
as opposed to capacitive coupling, is that: A. Transformers Transformers can’t match match impedance impedances. s. B. Transformers Transformers can’t work above above audio audio frequencies. C. Transf Transforme ormers rs cost cost more. D. Transformers Transformers reduce the gain. gain.
Question
Question An advantage of impedance coupling
compared to RC coupling is __. A. B. C. D.
Higher Higher effic efficienc iency y Lower Lower powe powerr Low Low heat heat Less distor distortio tion n
12
6/21/2014
Question A disadvantage of RC coupling is ___.
A. B. C. D.
Low Low powe powerr High High effici efficienc ency y Low Low effici efficien ency cy High High distorti distortion on level level
>>Bringing YOU Forward
DIFFERENTIAL AMPLIFIERS
Differential Amplifiers
Common Emitter and Common Base Configuration
• An amplifier that operates with two
possible inputs and two possible outputs. • It operates on the difference between two inputs.
The Basic Differential Amplifier • If Common-Emitter
and Common-Base Configuration is combined, the basic Differential Amplifier is formed.
>>Bringing You Forward
POSSIBLE BOARD QUESTIONS
13
6/21/2014
Question A differential amplifier ___.
A. B. C. D.
Is a part part of an op-am op-amp p Has two output outputss Has one input input and one one output output a and b are correct correct
Question Differential amplifier in the
mode ___. A. Opposite Opposite polarity polarity signals signals are applied applied to the inputs B. The gain is unity unity C. The outputs outputs are different different amplitudes amplitudes D. Only one one supply supply voltage voltage is is used
Question Differential gain is ___.
A. B. C. D.
Question When the two input terminals of a diff
Very Very high high Very ery llow ow Dependent Dependent on the the input input voltage voltage Abou Aboutt 100 100
amp are grounded, A. B. C. D.
Question One source of output error voltage is
A. B. C. D.
differential
Input Input bias bias curren currentt Difference Difference in collecto collectorr resistors resistors Tail Tail cur curren rentt Common-mod Common-mode e voltage voltage gain
The base base currents currents are are equal equal The collecto collectorr currents currents are equal equal An output output error voltage voltage usually usually exists exists The ac output output voltage voltage is zero zero
Question An amplifier basically constructed from
two transistors and whose output is proportional to the difference between the voltages applied to its two inputs. A. B. C. D.
differ different ential ial amplifier amplifier cascod cascode e ampl amplifi ifier er comple complemen mentary tary amplifi amplifier er quasi-comple quasi-complementary mentary amplifier amplifier
14
6/21/2014
Operational Amplifiers • It is an amplifier which is designed to be
used with other components to perform either computing functions or some type of transfer operation such as filtering. >>Bringing YOU Forward
OPERATIONAL AMPLIFIERS (OP-AMPS)
Characteristic of Op-Amp
Block Diagram of Op-Amps
• Very High Gain • Very High Input
Impedance • Very Low Output Impedance • Very Wide Bandwidth
Slew Rate
OP-AMP AC Consideration
• The maximum rate of change of the
output voltage in response to a step input voltage. • The slew rate is dependent upon the high-frequency response of the amplifier stage within the op-amp.
Guessing Time
15
6/21/2014
Common-Mode Rejection Ratio (CMRR)
OP-AMP CMRR
• The measure of an amplifier’s ability to
reject common-mode signals. • It is the ratio of the open-loop gain of and the common-mode gain of the Opamp.
AC Considerations-'nity Gain !( )roduct
OP-AMP Circuit Configurations • • • • • • •
Inverting Non-Inverting Voltage Follower Summing Subtractor Integrator Differentiator
Inverting Configuration • The input signal is
connected to the inverting input of the Op-Amp. • The output signal is inverted with respect to the input.
INVERTING Amplifier
Non-Inverting Configuration • The input signal is
directly connected to the inverting input of the Op-Amp. • The output is Inphase with the input.
Non-*n+ertingAmplifier
16
6/21/2014
Non-INVERTING Amplifier
VOLTAGE FOLLOWER
V&"TAG# V&"TA G# ,olloer
Summing Amplifier
Summing Amplifier
SUMMING Amplifier
• The output level is
determined by adding the input signals together although the output signal will be the opposite polarity compared to the sum of the input signals.
S'!TRACT&R or *,,#R#NC*NG Amplifier
SUBTRACTOR or Differencing Amp
INTEGRATOR INTEGRATOR Circuit
*NT#GRAT&R
*,,#R#NT*AT&R
17
6/21/2014
DIFFERENTIATOR DIFFERENTIATOR Circuit
OP-AMP as a COMPARATOR
!ac/ to &)-A0) #lectrical Caracteristics
C0RR
Question An integrated IC OP-AMP normally has
___.
>>Bringing You Forward
POSSIBLE BOARD QUESTIONS
A. B. C. D.
Two inputs inputs and two output output Two input inputss and one outpu outputt Single output and single input Eigh Eightt pins pins
Question Which of the following characteristics
does not apply to an op-amp? A. B. C. D.
High High gai gain n High High input input imped impedanc ance e Low Low pow power er Low input input impe impedan dance ce
Question An application of an operational amplifier in which the output signal is determined by the sum of the input signals multiplied by the gain; Eout = Gain(E1+E2+…) A. B. C. D.
magnet magnetic ic amplif amplifier ier summin summing g ampli amplifie fierr differ differenc ence e amplifi amplifier er scalin scaling g amplifi amplifier er
18
6/21/2014
Question What is the ideal value of
A. B. C. D.
CMRR?
Zero Nega Negati tive ve Infi Infini nite te One
If the mind keeps thinking “You've had enough” But the heart keeps telling t elling you “Don't give up” Who are we to be questioning, Wondering “what is what?” Don't give up, through it all JUST STAND UP! - From the song “Just stand Up”
OSCILLATORS • Oscillator is a circuit that produces a
Oscillators Fernando Victor V. de Vera ECE, Master of Technology (MT)
[email protected] [email protected]
Conditions for Oscillation
periodic waveform on its output with only the dc supply voltage as an input. !C
Oscillator
Conditions of Oscillation: The BARKHAUSEN CRITERION
• The phase shift around the feedback
• To start oscillation,
loop must be effectively 0 or 360 degrees. • The voltage gain around the closed loop feedback loop (loop gain) must equal to 1 (unity).
• To sustain
Loop Gain >1
oscillation, Loop Gain = 1
19
6/21/2014
Conditions of Oscillation: The BARKHAUSEN CRITERION • Damping –
LoopGain1
Oscillators Stability Requirement • Amplitude Stability – refers to the ability
of the oscillator to maintain a constant amplitude in the output waveform. • Frequency Stability – refers to the ability of the oscillator to maintain its operating frequency.
• Steady Oscillation –
LoopGain=1
Factors Affecting Stability • Short-Term Stability Load – Load Bias – Bias • Long-Term Stability Component Characteristic – Component (component aging, changes in temperature and humidity)
Components of Oscillator • Amplification • Frequency Determining Device • Regenerative Feedback
Classification of Oscillators • Sinusoidal • Non-Sinusoidal
PROBABLE BOARD QUESTIONS…
20
6/21/2014
Probable Board Question No.1:
Probable Board Question No.2:
• Which condition must exist for a circuit
• Which of the following is not an essential
to oscillate?
part of an oscillator?
– A. It must have a negative feedback
– A. source of energy that supply the losses in
sufficient to cancel the input – B. It must have a gain of less than 1 – C. It must have a positive feedback sufficient to overcome losses – D. It must be realized
tank circuit. – B. a resistor IC combination circuit – C. resonant circuit consists of inductance and capacitance – D. regenerative feedback circuit
Sinusoidal Oscillators • A sinusoidal oscillator is a device that
produces a sine-wave output signal. • The output of a sinusoidal oscillator
SINUSOIDAL OSCILLATORS
38
Filters and Oscillators
What should be the phase
shift around the feedback loop in order to oscillate? a.90 a. 90 degrees degrees b.180 degrees c. 270 degrees degrees d.360 degrees
should be constant in amplitude and frequency.
39
Filters and Oscillators
The attenuation of the
feedback circuit is 0.2. What should be the gain of the amplifier? a. 20 200 0 b.20 c. 50 d.5
21
6/21/2014
42
Filters and Oscillators
What should be the closed
loop voltage gain of an oscillator to start up? a.1 b.>1 c. 1MHz).
LC OSCILLATORS
Types of Feedback for LC Oscillators
Types of LC Oscillator • • • •
Armstrong Oscillator
Armstrong Oscillator Hartley Oscillator Colpitts Oscillator Clapp Oscillator
Armstrong Oscillator
• Armstrong Oscillator is used to produce a
sine-wave output of constant amplitude and a fairly constant frequency within the RF range. • It uses an LC circuit to establish the frequency of oscillation. • It uses Class C amplifier with self-bias. • Its frequency is fairly stable, and amplitude relatively constant.
25
6/21/2014
Hartley Oscillator
Hartley Oscillator
• Hartley Oscillator is an improvement of
Armstrong Oscillator. • Hartley Oscillator can generate a wide
range of frequencies and very easy to tune.
Colpitts Oscillator
Colpitts Oscillator
• Colpitts Oscillator is similar to Hartley
Oscillator except that two capacitors are used in the tank circuit instead in stead of a tapped coil. • Colpitts Oscillator has fairly good frequency stability, stability, easy to tune and can have a wide range of frequencies.
Clapp Oscillator
Clapp Oscillator
• Clapp Oscillator is a variation of Colpitts
Oscillator. • The basic difference is an additional
capacitor Cs in series with the inductor in the resonant feedback circuit.
26
6/21/2014
65
Filters and Oscillators
For frequencies greater
than 1MHz, what types of oscillators are used? a.LC b.RC c. Phase-shi Phase-shift ft d.Wien-bridge
68
Filters and Oscillators
Q of the coil increases, what happens to the resonant frequency? a. Remains Remains constant constant b.Increase c. Decrea Decrease se d.Stabilize
Filters and Oscillators
A self-excited oscillator in
which the tank circuit is divided into input and feedback portions by an inductive voltage divider. a. Clap Clapp p b. Armstro Armstrong ng c. Collp Collpits its d. Hartley Hartley
Filters and Oscillators
Colpitts oscillator contains a
tank circuit in its feedback circuit with how many capacitors and inductors? a. 2, 1 b.1, 2 c. 1, 1 d.2, 2
In a Colpitts oscillator, as the
71
67
69
Filters and Oscillators
What do you call the
oscillator circuit that uses tapped coil in the tuned circuit? a. Clapp Clapp b.Armstrong c. Collpi Collpits ts d.Hartley
72
Filters and Oscillators
A variation of the collpits
oscillator that makes use of series resonance rather than parallel. a. Clapp Clapp b.Armstrong c. Modified Modified Collpits Collpits d.Hartley
27
6/21/2014
73
Filters and Oscillators
Armstrong oscillator uses
what coil? a.Tapped coil b.AF transformer coil c. Tickler Tickler Coil d.Magnetic coil
Common Crystals
Piezoelectric Effect • Crystal vibrates at a constant rate when
it is exposed to an electric field. • The physical dimensions of the crystal determine the frequency of vibration. • Cutting the crystal to specific dimensions can produce crystals that have very exact frequency ratings.
Crystal Controlled Oscillator
• Rochelle salt has the best piezoelectric
properties but is very fragile. • Tourmaline Tourmaline is is very tough, but its vibration rate is not as stable. • Quartz Quartz crystals crystals fall between the two extremes and are the most commonly used. Quartz crystals are made from silicon dioxide (SiO2 ( SiO2). ).
Crystal-Controlled Oscillator
Frequency Response of Crystal Controlled Oscillator
28
6/21/2014
81
Filters and Oscillators
The material with the
piezoelectric effect is
PROBABLE BOARD QUESTIONS…
82
a.Quartz b.Rochelle salts c. Tourmali Tourmaline ne d.All the above
Filters and Oscillators
Crystals have a very
a.Low Q b.High Q c. Small Small inductance inductance d.Large resistance
Non-Sinusoidal Oscillators • Non-sinusoidal Oscillators generate
complex waveforms such as square, rectangular, trigger, sawtooth and trapezoidal waveforms. • Also called RELAXATION OSCILLATORS.
NON-SINUSOIDAL OSCILLATORS
Periodic Waveforms • A waveform which undergoes a pattern
of changes, returns to its original pattern, and repeats the same pattern of changes is called a PERIODIC waveform.
29
6/21/2014
Types of Periodic Waveforms
Square Wave
Types of Waveform Generators
Multivibrators • The type of circuit most often used to
• • • •
generate square or rectangular waves is the multivibrator. • Three Types:
Multivibrators Blocking Oscillators Sawtooth Oscillators Trapezoidal Oscillators
• Astable Multivibrator • Monostable Multivibrator • Bistable Multivibrator
Multivibrators: Summary Multivibrator Other Name
Stable States
Timing Needs Capacitors Trigger?
Astable
Clock, Freerunning
0
2
No
Monostable
One Shot, 1 Pulse Regenerator Regenerator
1
Yes
Bistable
Flip-Flop
0
Yes
2
PROBABLE BOARD QUESTIONS…
30
6/21/2014
90
Filters and Oscillators
For a BMV, ___.
a. The base resistor resistorss are connected to Vcc b.The feedback is coupled trough two resistors c. The feedback feedback is coupled coupled trough two capacitors d.The base resistors are connected to ground.
94
Filters and Oscillators
A two-state circuit that
has zero, one or two stable output states. a.Bistable multivibrator b.Monostable multivibrator c. Astable Astable multivibr multivibrator ator d.Multivibrator
Probable Board Question No.15: • The three types of multivibrators are C. Bistable • A. Astable D. Multistable • B. Monostable – A. A, B, C, and D – B. A, C, and D – C. B, C, and D – D. A, B, and C
91
Filters and Oscillators
The trigger pulses in vibrator
circuits ___.
a. Positive and and of sufficient amplitude b.Over rides the negative supply to the base c. Both Both a and and b d.None of these
April 2006 Board Question: • What type of circuit is used to produce
square or rectangular waves? – A. Sinusoidal generator – B. Multi-vibrator – C. Non-sinusoidal generator – D.Wave generator
Probable Board Question No.16: • In an astable multivibrator, which
components determine the pulse repetition frequency? – A. LC coupling networks – B. RC coupling networks – C. direct coupling – D. impedance coupling
31
6/21/2014
Short History of Microelectronics
MICROELECTRONICS Engr. Fernando Victor V. de Vera BSECE MT
• Integrated Circuits – Monolithic IC: Jack Kilby (1958, Texas Instruments) – Robert Noyce (1959) – Added a metal layer for interconnecting components in the chip.
Microelectronics MICROELECTRONICS is defined as that • MICROELECTRONICS area of technology associated with and applied to the realization of electronic systems made of extremely small electronic parts or elements. • Normally associated with Integrated Circuit (IC), but not only IC’s
1. The area of of technology technology associ associated ated with and applied to the realization of electronic systems made of extremely small electronic parts or elements. a. Miniat Miniaturi urizat zation ion b. Microelect Microelectronic ronicss c. Nanote Nanotechn chnolo ology gy d. Nanoelectr Nanoelectronics onics
POSSIBLE BOARD QUESTIONS
2. Which of the following is a problem associated with the use of vacuum tubes? a. Heat Heat b. Long warm-up warm-up time c. High High power power require requiremen mentt d. All of of the above above
32
6/21/2014
3. Building a system on modules or blocks where each module perform a necessary function of the system. a. b. c. d.
4. An epoxy board on which the circuit leads have been added which reduces weight and eliminates point-to-point wiring a. Mother Motherboa board rd b. PCB c. Integr Integrate ated d circui circuitt d. ProtoProto-boa board rd
Modula Modularr packagi packaging ng Block Block packagi packaging ng Func Functi tion onali ality ty Repa Repair ir
Integrated Circuit (IC) • Consists of elements inseparably
associated and formed on or within a single SUBSTRATE (mounting surface). • The circuit components and all interconnections are formed as a unit.
Limitations of IC Technology Technology • Impractical to create inductor – Inductors = coil • High power devices are not possible – Example: High-Power amplifiers
Advantages of the IC Technology • • • • • •
Compactness High Speed Low Power Requirement Reliability Ease of Maintenance Modular Construction
Linear vs. Digital ICs • LINEAR IC – A linear IC is used to process analog signals such as voices, music, and radio transmissions. – The term “linear” arises from the fact that, in general, the amplification factor is constant as the input amplitude varies.
• DIGITAL IC – A digital IC, also s ometimes called a digital-logic IC, operates using just two states, called high (logic 1) and low (logic 0)
33
6/21/2014
Types of Linear IC 1. OP-AMP OP-AMP (Operational (Operational Amplifie Amplifier) r) 2. Voltage Voltage Regulator Regulatorss (78xx, 79xx, 79xx, 317, 337, etc) 3. Time Timerr IC 4. Analog Analog Multiplexe Multiplexerr 5. Compar Comparato atorr IC
Digital IC • BIPOLAR Types – TTL (Transistor-Transistor Logic) – ECL (Emitter-Coupled Logic) • MOS (Metal-Oxide Semiconductor) Types – CMOS (Complementary MOS) – NMOS/PMOS (N-Channel MOS/ P-Channel MOS)
Component Density • COMPONENT DENSITY is the number of
elements per chip in an IC. • There is an absolute limit on the component density that can be attained; it is imposed by the atomic structure of the semiconductor material. • A logic gate will never be devised that is smaller than an individual atom.
Small Scale Integration (SSI) • With less than 10 gates per chip. • Example: Basic logic gate packages
(7400, 7404, etc)
Component Density • • • • • •
SSI (Small Scale Integration) MSI (Medium Scale Integration) LSI (Large Scale Integration) VLSI (Very Large Scale Integration) ULSI (Ultra- ) ELSI (Extremely- )
Medium Scale Integration (MSI) • There are 10 to 100 gates per chip. • An advantage of MSI (in a few
applications) is that fairly large currents can be carried by the individual gates. • Both Bipolar and MOS technologies can be adapted to MSI.
34
6/21/2014
Large Scale Integration (LSI)
Very Large Scale Integration (VLSI)
• There are 100 to 1000 gates per
• Have from 1,000 to 10,000 components
semiconductor chip. • This is an order of magnitude (a factor of 10) more dense than MSI. • Electronic wristwatches, single-chip calculators, and small microcomputers are examples of devices using LSI ICs.
per chip. • This is an order of magnitude more dense than LSI. • Complex microcomputers, and peripheral circuits such as memory storage ICs, are made using VLSI.
Ultra- and Extremely- LSI (ULSI/ELSI) • Have more than 10,000 gates in a chip.
Summary of Component Densities Level of Integration !ensit"#
Number of $ates
SSI (Sall Scale Integration! Integration!
"10
#SI (#e$iu Scale Integration! Integration!
10 % 100
&SI (&arge Scale Integration! Integration!
100 % 1,000
'&SI ('er ('er &arge Scale Integration! Integration!
1,000 % 10,000
)&SI, *&SI ()ltra-, *+treel- &SI!
10,000
14. Allow thousands of elements in a single chip. a. LSI and VLSI VLSI b. Diffu Diffusio sion n c. SSI SSI and and MSI MSI d. Mask Masking ing
POSSIBLE BOARD QUESTIONS
35
6/21/2014
15. Generally applied to integrated circuits consisting of from 1,000 to 2,000 logic gates or from 1,000 to 64,000 bits of memory. a. SSI b. MSI MSI c. LSI d. VLSI VLSI
3 Types of ICs (Based on the Material and Construction) • MONOLITHIC • FILM – Thin Film – Thick Film • HYBRID
16. Used in integrated circuits containing over 2,000 logic gates or greater than 64,000 bits of memory. a. SSI b. MSI c. LSI d. VLSI VLSI
Monolithic IC INTEGRATED CIRCUITS are • MONOLITHIC INTEGRATED those that are formed completely within a semiconductor substrate. • These ICs are commonly referred to as SILICON CHIPS.
Film ICs • 2 Categories: – THIN Film – THICK Film • Film components are made of either
conductive or nonconductive material that is deposited in desired patterns on a ceramic or glass substrate. • Film can only be used as PASSIVE circuit components, such as resistors and capacitors.
Hybrid ICs • HYBRID INTEGRATED CIRCUITS combine
two or more integrated circuit types or combine one or more integrated circuit types and DISCRETE (separate) components.
36
6/21/2014
47. Microcircuit refers to any component containing what types of elements? a. Microe Microelec lectro tronic nicss b. Integrated Integrated circuits circuits c. Passiv Passive e elem element entss d. Activ Active e elements elements
POSSIBLE BOARD QUESTIONS
48. Components made up exclusively of discrete elements are classified as what type of electronics? a. Disc Discre rete te b. Miniat Miniature ure c. Pass Passiv ive e d. Acti Active ve
6. Consist of elements inseparably associated and formed on or within a single substrate. a. Mother Motherboa board rd b. PCB c. Integr Integrate ated d circui circuitt d. ProtoProto-boa board rd
7. Which of the following are classifications of integrated circuits? a. Mono Monoli lith thic ic b. Film Film c. Hy Hyb brid rid d. All of thes these e
8. IC’s that are formed completely within a semiconductor substrate. a. Mono Monoli lithi thicc b. Film Film c. Hy Hyb brid rid d. All of thes these e
37
6/21/2014
9. Other term for a monolithic IC. a. Silico Silicon n chip chip b. Chip Chip c. Die d. All of thes these e
10. Monolithic IC’s contains: a. Passive Passive elements elements only b. Active Active elements elements only c. Both Both active active and Pass Passive ive d. None None of thes these e
Fernando Victor V. de Vera ECE, Master of Technology
SOLID STATE DEVICES
END OF SESSION
Electrical Classification of Materials
Solid State Devices • Operates by virtue of the movement of
• Conductor • Insulator • Semiconductor
electrons with solid piece of semiconductor material
227
Con"uctor
228
38
6/21/2014
Conductor • A material with LESS THAN 4 VALENCE
ELECTRONS. • Copper (Cu), Silver (Ag), Gold (Au) and Aluminum (Al)
229
#nsulator
230
Materials Conductivity • • • • •
Silver Copper Gold Aluminum Iron
Insulator
63.01 x 106 S/m 59.60 x 106 S/m 45.20 x 106 S/m 37.80 x 106 S/m 10.44 x 106 S/m
VALENCE • A material with MORE THAN 4 VALENCE ELECTRONS. • glass, mica, hard rubber
231
Semiconductor
S$micon"uctor
232
Energy Gap (Eg) Comparison
• A material with EXACTLY 4 VALENCE
ELECTRONS. • Semiconductors have electrical characteristics in between conductors and insulators. • SILICON, GERMANIUM are examples of semiconductor materials.
%n$r&y 'a( )%&* Com(arison
233
+on"in& of Atoms
234
39
6/21/2014
Energy Gaps • • • • • •
Silicon Germanium Silicon Carbide Aluminum Phosphide Gallium Arsenide Indium Phosphide
Bonding of Atoms
1.11 eV 0.67 eV 2.86 eV 2.45 eV 1.43 eV 1.35 eV
• Ionic Bond • Metallic Bond • Covalent Bond
235
236
#onic +on"
Ionic Bond
Metallic Bond
• Results from attractive forces between
• Results from attractive forces between a
positive and negative ions or between pairs of oppositely charged ions.
group of positive ions and a sea of electrons that are free to move about among its ions.
237
M$tallic +on"
Co,al$nt +on"in&
238
Covalent Bonding • Results when atoms
SHARE THEIR VALENCE ELECTRONS with other atoms . • The shared electrons are attracted simultaneously to two atoms resulting in a force that holds them together. Con"uction in S$micon"uctors
239
240
40
6/21/2014
Conduction in Semiconductors
Electron Flow
• Electron current flow • Hole current flow
241
%l$ctron lo.
Hole Flow
242
ol$ lo.
Types of Semiconductor Materials • Intrinsic Material • Extrinsic Materials – A Semiconductor that – Semiconductor is FREE FROM materials with SOME IMPURITIES, such as IMPURITIES ADDED to Silicon or Germanium. change its electrical properties. – The process of adding impurities is called DOPING.
y($s of S$micon"uctor mat$rials
243
y($ of %trinsic Mat$rials
Type of Extrinsic Materials
Type of Extrinsic Material
• N-TYPE
• P-TYPE
SEMICONDUCTORS
SEMICONDUCTORS
– An extrinsic
– An extrinsic
semiconductor material formed by adding DONOR impurities, such as as PENTAVALENT atoms. – Majority carriers are ELECTRONS – Minority carriers are HOLES y($ of %trinsic Mat$rial
244
semiconductor material formed by adding ACCEPTOR impurities, such as TRIVALENT atoms. – Majority carriers are HOLES – Minority carriers are ELECTRONS 245
y($s of !o($s
246
41
6/21/2014
Question
Types of Dopes • DONOR or
• ACCEPTOR or
PENTAVALENT ATOMS • N-TYPE
TRIVALENT ATOMS • P-TYPE
– PHOSPOROUS – ANTIMONY
The process of adding
– GALLIUM
• ALUMINUM • INDIUM – BORON
– ARSENIC – BISMUTH
S$micon"uctor!io"$s
impurities in a semiconductor material. a.growing b.diffusion c. doping doping d.depleting
247
The acceptor level in a doped
semiconductor
a. is near the valence band band level b.is near the conduction level c. is exactly exactly in between between the the conduction and valence band d.will depend on the concentration of doping
248
The potential required to
remove a valence electron a.valence potential b.threshold potential c. critical critical potential potential d.ionization potential
249
The movement of charge
Impurities with five
carriers in a semiconductor even without the application of electric potential. a. diffusion diffusion current current b.conventional current c. drift drift curren currentt d.saturation current
250
valence electrons. a.Acceptor b.donor c. Trivalen Trivalentt d.pentavalent 251
252
42
6/21/2014
In a semiconductor material,
An example of an
what will happen to the number of free electrons when the temperature rises?
elemental semiconductor. a.Germanium (Ge) b.Gallium Arsenide (GaAs) c. Gallium Gallium Phosphide Phosphide (GaP) d.Aluminum Arsenide (AlAs) 253
Current flow in a
semiconductor that is due to the applied electric field. a.diffusion current b.conventional current c. drift drift velocity velocity d.drift current
a. increases increases b.decreases exponentially c. decrea decreases ses d.remains the same
Which of the following is
an example of a compound semiconductor? a.Gallium Arsenide (GaAs) b.Gallium Phosphide (GaP) c. Aluminum Aluminum Arsenide Arsenide (AlAs) d.All of the above
255
If the substance used in
doping has less than four valence electrons, it is known as a. acceptor acceptor b.donor c. trival trivalen entt d.pentavalent
254
257
256
Theoretically, where does
the conduction of holes occur in a doped semiconductor? a. conduction conduction band band b.forbidden band c. valence valence band d.empty d. empty band band 258
43
6/21/2014
Typically, how how much energy
is required for a valence electron to move to the conduction band for a doped semiconductor?
The electrical resistance of a
semiconductor material will _____ as the temperature increases. a. increase increase b.increase exponentially c. decrea decrease se d.not d. not change change
a. 0 eV eV b. 0.05 eV c. 1.0 1.0 eV eV d. 5.0 eV 259
260
The PN Junction • When the P-TYPE
material and N-TYPE material are BROUGHT TOGETHER, they form a so-called PN JUNCTION.
Semiconductor Diodes
$ P unction
261
Formation of Depletion Region
Barrier Potential • The POTENTIAL
• The region created by
DIFFERENCE of the electric field across the depletion region is the AMOUNT OF VOLTAGE required to move electrons through the electric field. • 0.7V for Silicon • 0.3 for Germanium • Barrier potential DECREASES as temperature INCREASES
the PN junction forming a barrier potential. • The DEPLETION refers to the fact that the region near the PN junction is DEPLETED of CHARGED CARRIERS due to diffusion across the junction.
+arri$r Pot$ntial
262
ormation of !$(l$tion $&ion
263
+iasin& t$ !io"$
264
44
6/21/2014
Biasing the Diode
Forward Bias
• BIAS refers to the use of a dc voltage to
• Is the condition that
ALLOWS CURRENT THROUGH THE PN JUNCTION to flow when a dc voltage is applied to a PN junction
establish a certain operating condition for an electronic device. • Types: – Forward Bias – Reverse Bias
265
or.ar" +ias
$,$rs$ +ias
266
Reverse Bias • Is the condition that
ESSENTIALLY PREVENTS CURRENT through the diode when a dc voltage is applied to a PN junction. • MINORITY CARRIERS – The EXTREMELY SMALL
CURRENT THAT EXIST IN THE REVERSE BIAS condition. 267
+r$a"o.nolta&$
268
Voltage-Current Characteristic of Diode
Breakdown Voltage • The MAXIMUM VOLTAGE the junction
diode can handle when reverse biased. • Also known as PEAK REVERSE VOLTAGE (PRV) OR PEAK INVERSE VOLTAGE (PIV)
olta&$-Curr$nt Caract$ristic of !io"$
269
!io"$ %ui,al$nt Circuit
270
45
6/21/2014
Diode Equivalent Circuit
Ideal Diode Model
• Ideal Diode Model • Simplified Diode Model • Linear Diode Model
• The diode is assumed
to a ZERO THRESHOLD VOLTAGE and has NO RESISTANCE when FORWARD BIAS.
271
#"$al !io"$ Mo"$l
272
Sim(lifi$" !io"$ Mo"$l
Simplified Diode Model
Linear Diode Model • The diode has
• The diode is
THRESHOLD VOLTAGE, Vth and FORWARD RESISTANCE.
assumed to have a threshold voltage but NO RESISTANCE.
273
in$ar !io"$ Mo"$l
Diode Resistance
DC or Static Resistance • DC or Static
• DC or Static Resistance • AC or Dynamic Resistance • Average AC Resistance
!C or Static $sistanc$
274
!io"$ $sistanc$
Resistance is the FORWARD RESISTANCE of the diode when in DC circuit analysis.
275
AC or !ynamic $sistanc$
276
46
6/21/2014
AC or Dynamic Resistance
Average AC Resistance
• AC or Dynamic
• Average AC
Resistance of the diode when in AC circuit analysis.
A,$ra&$ AC $sistanc$
Resistance is the forward resistance of the diode in AC circuit analysis.
277
When a diode is reverse biased the
depletion region widens, since it is in between positively charge holes and negatively charge electrons, it will have an effect of a capacitor, this capacitance is called what? a. diffusion diffusion capacita capacitance nce b. storage storage capacit capacitance ance c. stray stray capaci capacitan tance ce d. transition transition capacita capacitance nce
%l$ct (ar r$ctifi$r !io"$s
278
In a semiconductor diode, the total
capacitance, that is the capacitance between terminals and electrodes, and the internal voltage variable capacitance of the junction is called a. diffusion diffusion capac capacitanc itance e b. transitio transition n capacita capacitance nce c. depletion depletion-regi -region on capacitanc capacitance e d. diode diode capacitanc capacitance e
279
280
In semiconductor materials,
What capacitance is
significant when the diode is forward biased? a. diffusion diffusion capacitance capacitance or storage capacitance b.transition capacitance c. depletiondepletion-region region capacitance capacitance d.stray capacitance
281
electrons have a higher value of mobility than holes, but which semiconductor material has the slowest electron-mobility? a. InSb InSb b. GaP GaP c. GaAs GaAs d. AlP AlP 282
47
6/21/2014
In the design of high power
semiconductor devices, it involves what factors?
Special-Purpose Diodes
a. making the size size of the semiconductor bigger b. packing packing the device into a bigger bigger case c. excellent excellent contact contact between between the semiconductor and the case d. all of thes these e
283
Zener Breakdown
Zener Diodes
• ZENER BREAKDOWN occurs in Zener
• Zener Diode is a s ilicon
PN junction device that differs from rectifier diodes because it is DESIGNED FOR OPERATION IN THE REVERSEBREAKDOWN REGION. • Developed by Dr. Carl Zener in 1934
diodes at low reverse voltage. • The Zener diode is heavily doped to reduce the breakdown voltage. • Types of reverse breakdown – Zener Breakdown – Avalanche Breakdown
285
$n$r +r$a"o.n
$n$r +r$a"o.n
Zener Breakdown
286
Avalanche Breakdown
• Breakdown voltage < 5V
A,alanc$ +r$a"o.n
284
$n$r !io"$s
• Breakdown voltage > 5V
287
$n$r !io"$ A((lication
288
48
6/21/2014
Zener Diode Application
Tunnel Diode • A tunnel diode is biased to operate in the
• Zener Diodes are
negative resistance region. • It can be used as an oscillator or an amplifier. • Tunnel diodes are also used extensively in highspeed switching circuits because of the speed of the tunneling action. (up to 5Ghz) • Developed by LEO ESAKI in 1958
often used as a type of of VOLTAGE REGULATOR for providing stable reference voltages.
289
unn$l !io"$
290
aractor
Varactor Voltage-Variable Capacitor is a device • Voltage-Variable that utilizes the variation of the PN junction capacitance when biased differently.
291
i&t-%mittin& !io"$ )%!*
292
Light-Emitting Diode (LED) arsenide (AlGaAs) - red and • Aluminum gallium arsenide (AlGaAs)
• A type of PN junction that emits light
infrared
when forward bias. • The large exposed surface area on one layer of the semiconductive material permits the photons to be emitted as visible light. • The process is called ELECTROLUMINESCENCE. Poto"io"$
phosphide (AlGaP) - green • Aluminum gallium phosphide (AlGaP) phosphide (AlGaInP) • Aluminum gallium indium phosphide (AlGaInP)
high-brightness orange-red, orange, yellow, and green phosphide (GaAsP) - red, • Gallium arsenide phosphide (GaAsP) orange-red, orange-red, orange, and yellow phosphide (GaP) - red, yellow and green • Gallium phosphide (GaP) nitride (GaN) - green, pure green (or • Gallium nitride (GaN) emerald emerald green), and blue also white (if it has an AlGaN Quantum Barrier) 293
294
49
6/21/2014
Photodiode nitride (InGaN) - near • Indium gallium nitride (InGaN) • • • • •
• Photodiode is a device that operates in
ultraviolet, bluish-green and blue Silicon carbide (SiC) carbide (SiC) as substrate — blue Silicon (Si) Silicon (Si) as substrate — blue (under development) Sapphire (Al2O3) Sapphire (Al2O3) as substrate — blue Zinc selenide (ZnSe) selenide (ZnSe) - blue Diamond (C) Diamond (C) - ultraviolet 295
REVERSE BIAS. • A Photodiode current increases as light strikes into its opening. • The photodiode has a small transparent window that allows light to strike the PN junction.
296
DIODE MAINTENANCE
DIODE MAINTENANCE • Diodes are rugged and efficient. • One of the greatest dangers to the diode
is heat. • THERMAL RUNAWAY – A conduction that exists when heat causes
more electron-hole pairs to b generated; which, in turn, causes more heat and may eventually cause diode destruction.
ransistors
Which semiconductor is
298
The charged-coupled device
(CCD) is a unique and versatile semiconductor structure invented in 1969 by
mostly used to detect near infrared? a.silicon b.germanium c. carbon carbon d.silicon carbide 299
a. W.S.Boyle and G.E. Smith Smith b. W.F. Davis and R. Huntington c. Cave and W. W. Blood Jr. Jr. d. H.H. Stellrecht and S. Meyer 300
50
6/21/2014
What semiconductor that
For an electroluminescent of
is good for hightemperature applications?
green and red lights, which semiconductor is best?
a.indium antimonide (InSb) b.gallium antimonide (GaSb) c. silicon silicon carbide carbide (SiC) d.diamond (C)
a. silicon silicon carbide carbide b.gallium arsenide c. indium antimonide antimonide d.gallium phosphide
301
Which of the following
302
The primary use of Zener
semiconductors has the smallest energy gap?
diode in electronic circuits. a.resistance regulator b.rectifier c. voltage voltage regulator regulator d.current regulator
a.ZnS b.Si c. Ge d.InSb 303
A diode that is especially
designed to operate as a voltage-variable capacitor. It utilizes the junction capacitance of a semiconductor diode. a. varac varacto torr b. varicap varicap c. varis varisto torr d. A and B are correct correct 305
304
The capacitance of a varactor
will ______ when the forward bias voltage is increase a. increase increase b.decrease c. exponentia exponentially lly decrease decrease d.not d. not change 306
51
6/21/2014
The ratio of the diode capacitance
Refers to a special type of
at a minimum reverse voltage to the diode capacitance at a maximum reverse voltage in a varactor diode.
diode which is capable of both amplification and oscillation. a. Junction Junction diode diode b.Tunnel diode c. Point Point contact contact diode diode d.Zene d. Zenerr diode
a. Tunin Tuning g ratio ratio b. Capacitan Capacitance ce ratio ratio c. Both Both a and and b d. None None of these these 307
A light emitting diode (LED) is to be
used in a circuit with a supply voltage of 5 V. What should be the value of the resistor needed by the LED to operate normally? a. 25 Ω b. 25 250 0Ω c. 25 kΩ kΩ d. 250 250 kΩ kΩ
309
308
The process of emitting
photons from a semiconductive material is called a. photoluminescence b.gallium arsenide c. electrolumi electroluminesc nescence ence d.gallium phosphide
310
Silicon and Germanium are
LED which emits infrared
not used in LEDs because ___.
radiation.
a. They emit heat instead of light b.They emit very low amount of emitted light c. They have have low thresho threshold ld voltage d.A and b are correct
a.GaAs b.GaAsP c. GaP GaP d.AlGaP 311
312
52
6/21/2014
A diode capable of
Schottky diodes are also
regulating current.
known as ___.
a.Constant-current diode b.Zener diode c. Current-controlled device d.All of these
a.Hot-carrier diode b.Tunnel diode c. PIN diode diode d.Point-contact diode 313
A diode consisting of
heavily doped p and n regions separated by an intrinsic region. a. Hot-carrier Hot-carrier diode diode b.Tunnel diode c. PIN diode diode d.Point-contact diode
314
A semiconductor diode which
employs graded doping where the doping level of the semiconductive materials is reduced as the pn junction is approached. a. Schott Schottky ky diode diode b. PIN diode diode c. Step-reco Step-recovery very diode diode d. Tunnel Tunnel diode diode
315
316
A semiconductor diode
constructed with heavily doped p and n germanium or gallium arsenide regions to have a very narrow depletion region.
Transistors
a. Schottk Schottky y diode diode b. PIN diod diode e c. Step-rec Step-recove overy ry diode d. Tunnel Tunnel diode diode 317
+i(olar unction ransistors )+*
318
53
6/21/2014
Transistors
Point-Contact Transistor
• The word is a contraction of TRANSfer
and resISTOR. • December 23,1947 the first transistor was demonstrated by Walter Brattain and John Bardeen.
ransistor in,$ntors :illiam Socl$y 319 )s$at$"*; on +ar"$$n;
320
Uses of BJT
Bipolar Junction Transistors (BJT) • BJT is constructed with three doped
semiconductor regions separated by two PN junctions. • BIPOLAR refers to TWO CHARGED CARRIERS: Electrons and Holes. • The Three Terminals: Emitter, Base and Collector
• Amplifier • Switch • Impedance Matching
321
y($s of +
322
Types of BJT
Transistor Operation
Reverse bias junction
Forward bias junction
ransistor
