1. Sedra/Smith Microelectronic Circuits 5/e
PowerPoint Overheads for
Sedra/Smith Microelectronic Circuits 5/e
©2004 Oxford University Press.

2. Microelectronics refers to the integrated circuit (IC) technology.
producing circuits that contains millions components in a silicon chip (100 mm2).
Ex) microprocessor
In this semester, we shall study
- electronics that can be
used singly (in the design of discrete circuits)
as components of an integrated-circuit (IC) chip.
- the design and analysis of interconnection of these devices.
- available IC chips and their applications in the design of electronic system.
Microelectronic Circuits - Fifth Edition Sedra/Smith

3. Why we should study the op amps here?
Part I
Devices and Basic Circuits
The most fundamental and essential topics for the study of electronic circuits.
Chap. 1: Introduction to Electronics
Chap. 2: Operational Amplifier*
Chap. 3: Diode
Chap. 4: MOS Field-Effect Transistors (MOSFETs)
Chap. 5: Bipolar Junction Transistor (BJTs)
* Op amp is, strictly speaking, not an basic electronic device.
Op amp’s internal circuit is complex (20 or more transistors).
Why we should study the op amps here?
Op amp is commercially available as an integrated circuit (IC) package.
Op amp has well-defined terminal characteristics. ? 3

4. V’i =Vi regardless of Ro. V’o =Vo regardless of RL.
Op amp has well-defined terminal characteristics.
1. The input impedance of an ideal op amp is supposed to be infinite.
Op amp Ro
i=0
V’i Ri
V’i =Vi regardless of Ro.
2. The output impedance of an ideal op amp is supposed to be zero.
Op amp Vo RL
V’o
V’o =Vo regardless of RL.
Microelectronic Circuits - Fifth Edition Sedra/Smith

5. Introduction to Electronics
Introduction to Electronics
The purpose of this chapter
To introduce some basic concept and terminology.
Signals
Signal amplification
Models for linear amplifier
Digital logic inverters
Circuit simulation using SPICE 5

6. speaker, monitor, printer Two representations of a signal source
Information
Transducer
Electrical Signal
Microphone, camera
speaker, monitor, printer
Two representations of a signal source
the Thévenin form, Rs is low the Norton form , Rs is high.
Microelectronic Circuits - Fifth Edition Sedra/Smith

7. Inverse Fourier transform
1.2 frequency spectrum of signals
Sine-wave voltage signal
amplitude Va
frequency f = 1/T Hz.
angular frequency ω = 2πf rad/s.
rms (root-mean-square, effective) value of ac value
A dc value that delivers the same time average power as the ac value does.
Fourier transform
Time domain
Frequency domain
Inverse Fourier transform
Microelectronic Circuits - Fifth Edition Sedra/Smith

8. Band Designations for Microwave
Spectrum of electromagnetic waves.
Old
New
Frequency Ranges (GHz) Ka K J
18-20 Ku X I
8-10 C H
6-8 G
4-6 S F
3-4 E
2-3 L D
1-2
UHF
0.5-1
Band Designations for Microwave
Frequency Ranges
Cell phones MHz, 1.8 GHz
Satellite TV GHz (USA)
무궁화 : 상향 GHz
하향 GHz
Microelectronic Circuits - Fifth Edition Sedra/Smith

9. ω0=2π/T : fundamental frequency
Periodic signal
Time domain
ω0=2π/T : fundamental frequency
Frequency domain
Frequency spectrum
Microelectronic Circuits - Fifth Edition Sedra/Smith

10. Non-periodic signal Time domain Frequency domain Frequency spectrum
Figure 1.6 The frequency spectrum of an arbitrary waveform such as that in Fig. 1.2.
Microelectronic Circuits - Fifth Edition Sedra/Smith

11. Frequencies of Some Common Signals
Audible sounds 20 Hz - 20 KHz
Baseband TV MHz
FM Radio MHz
Television (Channels 2-6) MHz
Television (Channels 7-13) MHz
Maritime and Govt. Comm MHz
Cell phones MHz, 1.8 GHz
Satellite TV GHz (USA)
무궁화 : 상향 GHz
하향 GHz
Microelectronic Circuits - Fifth Edition Sedra/Smith

12. 1.3 Analog and digital signals
Analog signal
Sampling
180 mV
Discrete-time signal
Quantization
Discretization
digitization
180=( )
Digital signal
Microelectronic Circuits - Fifth Edition Sedra/Smith

13. N binary digits
N bits
Figure 1.9 Block-diagram representation of the analog-to-digital converter (ADC).
b0: the least significant bit (LSB), bN-1: the most significant bit (MSB),
Increasing the number of bits reduces the quantization error and increases the resolution of the ADC.
ADC, DAC : Chapter 9.
Although the digital processing of signals is at present all-pervasive, there remain many signal processing functions that are best performed by analog circuits.
A good electronic engineer must proficient in the design of both analog and digital circuits, or mixed-signal or mixed-mode design as its currently known.
Microelectronic Circuits - Fifth Edition Sedra/Smith

14. Notational Conventions
1.4 Amplifiers
Notational Conventions
Total signal = DC bias + time varying signal (ac)
Resistance and conductance - R and G with same subscripts will denote reciprocal quantities. Most convenient form will be used within expressions.
Microelectronic Circuits - Fifth Edition Sedra/Smith

15. 1.4.2 Amplifier Circuit Model
1.4.1 Signal Amplification
1.4.2 Amplifier Circuit Model
Preamplifier: high voltage gain
Power Amplifier:
modest amount of voltage gain
substantial current gain
Figure (a) Circuit symbol for amplifier. (b) An amplifier with a common terminal (ground) between the input and output ports.
Microelectronic Circuits - Fifth Edition Sedra/Smith

16. 1.4.4 Power Gain and Current Gain
1.4.3 Voltage Gain
1.4.4 Power Gain and Current Gain
Transfer characteristic of a linear voltage amplifier with voltage gain Av.
Microelectronic Circuits - Fifth Edition Sedra/Smith

17. 1.4.5 Expressing Gain in Decibels (Decibels are only for power !)
if RL=RI ,
Microelectronic Circuits - Fifth Edition Sedra/Smith

18. 1.4.6 The Amplifier Power Supplies
Amplifiers can not generate power or energy.
Power for amplification should be supplied by dc power supply (voltage regulator) or battery.
Some amps use only one power supply.
Figure An amplifier that requires two dc supplies (shown as batteries) for operation.
Energy conservation
Amplifier efficiency
The power efficiency is an important performance parameter for amplifiers that handles large amount of power. (power amp as output amplifiers of stereo systems, amps in cell phones even though the power is low.)
Microelectronic Circuits - Fifth Edition Sedra/Smith

19. EXAMPLE 1.1
±10 V power supplies, 1 V peak sinusoidal input, mA peak sinusoidal input current, 9 V peak sinusoidal output, 1 kΩ load, 9.5 mA from each power supplies.
Find the voltage gain, the current gain, the power gain, the power drawn from the dc power supplies, the power dissipated in the amplifier, and the amplifier efficiency.
Microelectronic Circuits - Fifth Edition Sedra/Smith

20. 1.4.8 Nonlinear Transfer Characteristics and Biasing
1.4.7 Amplifier Saturation
Practically speaking, the amplifier transfer characteristic remains linear over only a limited range of input and output voltages.
1.4.8 Nonlinear Transfer Characteristics and Biasing
Figure An amplifier transfer characteristic that is linear except for output saturation.
In practical amplifiers the transfer characteristic may exhibit nonlinearity other than output saturation.
* Let’s consider an amplifier that is operated from a single positive power.
Microelectronic Circuits - Fifth Edition Sedra/Smith

21. Small signal approximation Otherwise, distortion in output signal!
dc bias point
= Quiescent point
Small signal approximation
Otherwise, distortion in output signal!
Figure (a) An amplifier transfer characteristic that shows considerable nonlinearity. (b) To obtain linear operation the amplifier is biased as shown, and the signal amplitude is kept small. Observe that this amplifier is operated from a single power supply, VDD.
Microelectronic Circuits - Fifth Edition Sedra/Smith

22. EXAMPLE 1.2 p21 Solution (a) Find L_ and L+ and corresponding υI .
(b) Find dc bias voltage VI and voltage gain for VO=5 V.
Solution
Figure A sketch of the transfer characteristic of the amplifier of Example 1.2. Note that this amplifier is inverting (i.e., with a gain that is negative).
Microelectronic Circuits - Fifth Edition Sedra/Smith

23. 1.5 Circuit Models for Amplifiers
Voltage Amplifiers (voltage input-voltage output)
Figure (a) Circuit model for the voltage amplifier. (b) The voltage amplifier with input signal source and load.
dependent source: Voltage controlled voltage source
Microelectronic Circuits - Fifth Edition Sedra/Smith

24. 1.5.2 Cascaded Amplifiers EXAMPLE 1.3
Figure Three-stage amplifier for Example 1.3.
Microelectronic Circuits - Fifth Edition Sedra/Smith

25. Other Amplifier Types
Can be measured with short-circuit. (current source)
= Transimpedance
Amplifier
Microelectronic Circuits - Fifth Edition Sedra/Smith

26. 1.5.4 Relationships between the Four Amplifier Models
Although for a given amplifier a particular one of the four models in Table 1.1 is most preferable, any of the four can be used to model the amplifier.
Simple relationships can be derived to relate the parameters of the various models.
These techniques are conceptually right, in actual practice more refined methods are employed in measuring Ri and Ro.
Microelectronic Circuits - Fifth Edition Sedra/Smith

27. We shall not pursue this further at this point.
The amplifiers considered so far are unilateral; that is, signal flow is in unidirectional, from input to output.
Most real amplifiers show some reverse transmission, which is usually undesirable but must nonetheless be modeled.
We shall not pursue this further at this point.
Complete models for linear two port networks : Appendix B.
Chapters 4 and 5 for high frequency models.
Microelectronic Circuits - Fifth Edition Sedra/Smith

28. EXAMPLE 1.4 Models for Bipolar Junction Transistor (BJT, Chap.5), p29
Figure (a) Small-signal circuit model for a bipolar junction transistor (BJT).
Base, Emitter, Collector
(b) The BJT connected as an amplifier with the emitter as a common terminal between input and output (called a common-emitter amplifier).
(c) An alternative small-signal circuit model for the BJT.
Microelectronic Circuits - Fifth Edition Sedra/Smith

29. (c) An alternative small-signal circuit model for the BJT.
(b) The BJT connected as an amplifier with the emitter as a common terminal between input and output (called a common-emitter amplifier).
(c) An alternative small-signal circuit model for the BJT.
Microelectronic Circuits - Fifth Edition Sedra/Smith

30. 1.6 Frequency Response of Amplifiers
The input signal can be expressed as the sum of sinusoidal signals of different frequencies.
1.6.1 Measuring the Amplifier Frequency Response
The resulting output is sinusoidal with the same frequency as the input.
1.6.2 Amplifier Bandwidth dB
3 dB
Microelectronic Circuits - Fifth Edition Sedra/Smith

31. 1.6.3 Evaluating the Frequency Response
Laplace Transform
(s: complex frequency)
1.6.4 Single-Time-Constant (STC) Networks
Single-Time-Constant (STC) Network :
a circuit that is composed of, or can be reduced to, one reactive component (inductance or capacitance) and one resistance
Appendix D
Responses of STC network to sinusoidal, step, and pulse inputs.
You should read, if you want to be a good engineer.
Microelectronic Circuits - Fifth Edition Sedra/Smith

32. Figure 1.22 Two examples of STC networks: (a) a low-pass network and (b) a high-pass network.
Microelectronic Circuits - Fifth Edition Sedra/Smith

33. Single-Time-Constant (STC) NetworksRe Im Im K Re 1
Microelectronic Circuits - Fifth Edition Sedra/Smith

34. Frequency Response Plot (Bode Plot) of STC network of Low-Pass Filter
Figure (a) Magnitude and (b) phase response of STC networks of the low-pass type.
Microelectronic Circuits - Fifth Edition Sedra/Smith

35. Frequency Response Plot (Bode Plot) of STC network of High-Pass Filter
Figure (a) Magnitude and (b) phase response of STC networks of the high-pass type.
Microelectronic Circuits - Fifth Edition Sedra/Smith

36. Frequency response of Voltage Amplifier
EXAMPLE 1.5, p36
Frequency response of Voltage Amplifier
Microelectronic Circuits - Fifth Edition Sedra/Smith

37. 1.6.4 Classification of Amplifiers Based on Frequency Response
(a) a capacitively coupled amplifier
(b) a direct-coupled amplifier
(c) a tuned or bandpass amplifier.
Ex) Audio Amplifier
The falloff of gain at high frequency
Internal capacitance Ci (previous slide)
The falloff of gain at low frequency
Coupling capacitance
Used to connect one amplifier to another
to simplify the design process of different amplifier
Quite large ( a fraction of μF ~a few tens of μF )
– very small reactance, but large at low frequency → voltage drop
High-pass STC
Microelectronic Circuits - Fifth Edition Sedra/Smith

38. Some applications require gain at low frequency down to dc.
Monolithic IC technology does not allow the fabrication of large coupling capacitors.
IC amplifiers are usually designed as directly coupled or dc amplifiers.
low-pass amplifier, low-pass filter
(b) a direct-coupled amplifier
Tuners for channel selection need gain only around center frequency.
Tuned amplifier, bandpass amplifier, bandpass filter.
(c) a tuned or bandpass amplifier.
Microelectronic Circuits - Fifth Edition Sedra/Smith

39. 1.7.1 Function of the Inverter υI υO
1.7 Digital Logic Inverters – the most basic element in digital circuit design
1.7.1 Function of the Inverter
Figure A logic inverter operating from a dc supply VDD. υI 1
0 (≈ 0 V) υO
1 (≈ VDD)
1.7.2 The Voltage Transfer Characteristic (VTC)
Signal amplifiers operate in the liner rage of transfer curve.
Digital application use of the gross non-linearity exhibited by the VTC.
Figure A sketch of the transfer characteristic of the amplifier of Example 1.2. Note that this amplifier is inverting (i.e., with a gain that is negative). p21
Microelectronic Circuits - Fifth Edition Sedra/Smith

40. 1.7.3 Noise Margin 1.7.4 The Ideal VTC
VIL : the maximum input value that υI can have while being interpreted by the inverter as represented as logic 0.
VIH : the minimum input value that υI can have while being interpreted by the inverter as represented as logic 1.
VOL : Output low level
VOH : Output high level
Transition region
1.7.3 Noise Margin
Great advantage of digital circuit over analog circuit.
Restoring the signal levels to standard level (VOL and VOH) when it is presented with corrupted signal level (within the noise margin).
1.7.4 The Ideal VTC
Maximum noise margin.
CMOS inverter is very close to realizing the ideal VTC.
Microelectronic Circuits - Fifth Edition Sedra/Smith

41. 1.7.5 Inverter Implementation
Figure (a) The simplest implementation of a logic inverter using a voltage-controlled switch
(b) equivalent circuit when υI is low
(c) equivalent circuit when υI is high. Note that the switch is assumed to close when υI is high.
FET, BJT
For FET, when υI is high, no current flow from υI through Ron to ground.
For BJT, when υI is high, current flow from υI through Ron to ground and from VDD to ground
However, when υI is high, current flow from VDD through R and Ron to ground.
Microelectronic Circuits - Fifth Edition Sedra/Smith

42. Figure A more elaborate implementation of the logic inverter utilizing two complementary switches. This is the basis of the CMOS (base on FET) inverter studied in Section 4.10.
PU: pull-up switch
PD: pull-down switch
VOH = VDD
No current flows.
VOL = 0
No current flows!
Figure Another inverter implementation utilizing a double-throw switch to steer the constant current IEE to RC1 (when υI is high) or RC2 (when υI is low). This is the basis of the emitter-coupled logic (ECL) studied in Chapters 7 and 11.
Microelectronic Circuits - Fifth Edition Sedra/Smith

43. Very-Large-Scale-Integration, VLSI
1.7.6 Power Dissipation of the (FET based) Inverter
At present, 100,000 gates or more can be fabricated on a single IC chip.
Very-Large-Scale-Integration, VLSI
It is very important to keep the power dissipation be minimum for low power consumption and low temperature.
This logic circuit will dissipate no power. Really?
υO1
When υI is low, no current flows. No power dissipation
When υI is high, the inverter dissipates approximately VDD2/R. Static Power Dissipation.
Microelectronic Circuits - Fifth Edition Sedra/Smith

44. Dynamic Power Dissipation
An inverter switched at a frequency f Hz exhibits a dynamic power dissipation,
Homework!
1.7.7 Propagation Delay
The transistors exhibit finite switching times.
RC time constant τ.
Load Capacitor!
The output y(t) at any time t of STC network to the step input is,
As the inverter is switched, current must flow through the switches to charge (and discharge) the load capacitance!
Input Capacitor!
Microelectronic Circuits - Fifth Edition Sedra/Smith

45. EXAMPLE 1.6 Y0+ = VOL =? =? Voffset = 0.1 V
Figure (a) The inverter circuit after the switch opens (i.e., for t  0).
Voffset = 0.1 V
(b) Waveforms of vI and vO. Observe that the switch is assumed to operate instantaneously. vO rises exponentially, starting at VOL and heading toward VOH .
Y0+ = VOL =? =?
Microelectronic Circuits - Fifth Edition Sedra/Smith

46. Input pulse Output pulse 10%, 90% of (VOL-VOH) of (VOL+VOH) fall time
rise time
fall time
Output pulse
Propagation delay
fall time
Transition High-to Low
rise time
Transition Low-to-High
Figure Definitions of propagation delays and transition times of the logic inverter.
Microelectronic Circuits - Fifth Edition Sedra/Smith

47. 1.8 Circuit Simulation Using SPICE (Simulation Program with Integrated Circuit Emphasis)
The use of computer programs to simulate the operation of electronic circuits has become an essential step in the circuit-build process before and after fabrication.
Circuit simulation enables the designer;
- To verify the design to meet specification when actual components (with their many imperfection) are used.
- To get additional insight into circuit operation.
- To fine-tune the final design prior to fabrication.
It is not a substitute for a thorough understanding of circuit operation !
It should be performed only a later stage in the design process after a paper-and-pencil design has been done !
PSpice is a commercial PC version of SPICE (Cadence).
PSpice A/D : analog and digital signal
OrCAD Capture CIS (Component Information System) : graphical interface ( referred in this book)
Microelectronic Circuits - Fifth Edition Sedra/Smith