The document provides information about the Pulse and Digital Circuits course at Matrusri Engineering College. It includes the course objectives, which are to analyze various pulse circuits and understand operational amplifiers. It also lists the course outcomes, such as being able to design multivibrators and analyze characteristics of operational amplifiers. The document then covers several topics that will be taught in the course, including linear wave shaping circuits, attenuators, and nonlinear wave shaping circuits like clippers and clampers.

1. MATRUSRI ENGINEERING COLLEGE
DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING
SUBJECT NAME: PULSE & DIGITAL CIRCUITS (PC233EC)
FACULTY NAME: Mrs. P.Sravani
MATRUSRI
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2. PULSE & DIGITAL CIRCUITS
COURSE OBJECTIVES:
 Analyze the behavior of linear and non linear wave shaping circuits.
 Analyze and design of Multivobrators.
 Understand the operation of OP-AMP and its internal circuits.
 Analyze the applications of OP-AMP and 555 Timer.
 5.Explain the operation of various data converter circuits and PLL.
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COURSE OUTCOMES:
 Construct different linear and non linear networks and analyse their response
to different input signals.
 Understand, analyse and design multivibrators and sweep circuits using
transistors.
 Analyse DC characteristics and AC characteristics for single/Dual input
Balanced/Unbalanced output configurations using BJTs and OP-AMP.
 Distinguish various linear and nonlinear applications of OP-AMP.
 Demonstrate the various applications of 555 Timer and analyse the operation
of the D/A and A/D converters.

3. UNIT-I: Linear wave shaping
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INTRODUCTION:
 A linear network is a network made up of linear elements only. A linear
network can be described by linear differential equations. The principle of
superposition and the principle of homogeneity hold good for linear networks.
 In pulse circuitry, there are a number of waveforms, which appear very
frequently. The most important of these are sinusoidal, step, pulse, square
wave, ramp, and exponential waveforms. The response of RC circuits to these
signals is described in this chapter.
 The process whereby the form of a non-sinusoidal signal is altered by
transmission through a linear network is called linear wave shaping.
 The process where by the form of a signal is changed by transmission through a
non-linear network is called Non-linear Wave Shaping.

4. OUTCOMES:
 To derive the response of high-pass and low-pass RC circuits to
different types of inputs like Sinusoidal, pulse, step, square, ramp
signals.
 To describe the application of high pass and low pass circuit as
Differentiator and integrator respectively.
 To understand the principles of working of uncompensated and
compensated attenuators and the operation of the attenuator circuit in
CRO probe.
 To study the principle of operation of various series and shunt clipping
circuits.
 To study the principle of operation of various clamping circuits and
verify the clamping circuit theorem.

5. MODULE-I: Linear wave shaping
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CONTENTS:
 High pass RC circuits with Step, Pulse, Square wave and Ramp inputs
 Low pass RC circuits with Step, Pulse, Square wave and Ramp inputs
 High pass RC circuit as Differentiator
 Low pass RC circuit as Integrator
OUTCOMES:
 To derive the response of high-pass and low-pass RC circuits to different
types of inputs like Sinusoidal, pulse, step, square, ramp signals.
 To describe the application of high pass and low pass circuit as Differentiator
and integrator respectively.

6. DEFINITION: It is the process of changing the shape of input signal
with linear / non-linear circuits.
Wave Shaping
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Types
 Linear Wave Shaping
 Non-linear Wave Shaping

7. DEFINITION: The process where by the form of a non-
sinusoidal signal is changed by transmission through a linear
network is called linear wave shaping.
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Linear Wave Shaping
Types
 High Pass RC Circuit.
 Low Pass RC Circuit.

8. Non-sinusoidal wave forms
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1. Step Waveform: A step voltage is one which
maintains the value zero for all times t<0 and
maintains the value V for all times t>0.

9. 2. Pulse Waveform: The pulse amplitude is V
and the pulse duration is tp.
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10. 3. Square Wave: A wave form which maintains
itself at one constant level V1 for a time T1 and
at other constant Level V11 for a time T2 and
which is repetitive with a period T=T1+T2 is
called a square-wave.
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11. 4.Ramp: A waveform which is zero for t < 0 and
which increases linearly with time for t > 0.
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12. High Pass RC Circuit
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 At zero frequency the reactance of the capacitor is infinity and so it
blocks the input and hence the output is zero. Hence, this capacitor is
called the blocking capacitor and this circuit, also called the capacitive
coupling circuit, is used to provide dc isolation between the input and
the output.
 Since this circuit attenuates low-frequency signals and allows
transmission of high-frequency signals with little or no attenuation, it is
called a high-pass circuit.

13. Sinusoidal Input
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14. Step Input
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The instantaneous change in voltage across the capacitor is given by

15. Pulse Input
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 The pulse input is the same as that for a step input and is given by
Vo(t) = V e-t/ RC.
At t = tp, Vo(t) = V = V e-t/RC .
 At t = tp, since the input falls by V volts suddenly and since the voltage
across the capacitor cannot change instantaneously, the output also falls
suddenly by V volts to Vp - V.
 Hence at t = t + , va(t) = Ve-tp /RC - V . Since Vp< V, Vp- V is negative. So
there is an undershoot at t = tp and hence for t > tp, the output is negative. For
t > tp, the output rises exponentially towards zero with a time constant RC
according to the expression (Ve-tp/RC - V)e-(t-tp)/RC- The output waveforms
for RC » tp, RC comparable to tp and RC « tp.

16. Square-Wave Input
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Expression for the percentage tilt

19. Ramp Input
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21. THE HIGH-PASS RC CIRCUIT AS A DIFFERENTIATOR
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22. THE LOW-PASS RC CIRCUIT
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 At zero frequency, the reactance of the capacitor is infinity (i.e. the
capacitor acts as an open circuit) so the entire input appears at the output,
i.e. the input is transmitted to the output with zero attenuation. So the
output is the same as the input, i.e. the gain is unity.
 As the frequency increases the capacitive reactance decreases and so
the output decreases. At very high frequencies the capacitor virtually acts
as a short-circuit and the output falls to zero.

23. Sinusoidal Input
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24. Step-Voltage Input
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Expression for rise time: When a step signal is applied, the rise time tr
is defined as the time taken by the output voltage waveform to rise
from 10% to 90% of its final value: It gives an indication of how fast
the circuit can respond to a discontinuity in voltage.

25. Relation between rise time and upper 3-dB frequency
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 Thus, the rise time is inversely proportional to the upper 3-dB
frequency. The time constant (Τ= RC) of a circuit is defined as the
time taken by the output to rise to 63.2% of the amplitude of the input
step. It is same as the time taken by the output to rise to 100% of the
amplitude of the input step, if the initial slope of rise is maintained

26. Pulse Input
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If the time constant RC of the circuit is very large, at the end of the
pulse, the output voltage will be Vp(t) = V(1 – e-tp/RC), and the output
will decrease to zero from this value with a time constant RC

27. Square-Wave Input
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 A square wave is a periodic waveform which maintains itself at one constant
level V’ with respect to ground for a time T1 and then changes abruptly to
another level V", and remains constant at that level for a time T2, and repeats
itself at regular intervals of T = T1 + T2.
 A square wave may be treated as a series of positive and negative steps. The
shape of the output waveform for a square wave input depends on the time
constant of the circuit. If the time constant is very small, the rise time will also
be small and a reasonable reproduction of the input may be obtained.

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29. Ramp Input
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30. THE LOW-PASS RC CIRCUIT AS AN INTEGRATOR
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As time increases, the voltage drop across C does not remain negligible
compared with that across R and the output will not remain the integral
of the input. The output will change from a quadratic to a linear
function of time.

31. If the time constant of an RC low-pass circuit is very large in comparison with the. time
required for the input signal to make an appreciable change, the circuit acts as an
integrator.
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1. It is easier to stabilize an integrator than a differentiator because the gain of an integrator
decreases with frequency whereas the gain of a differentiator increases with frequency.
2. An integrator is less sensitive to noise voltages than a differentiator because of its limited
bandwidth.
3. The amplifier of a differentiator may overload if the input waveform changes very rapidly.
4. It is more convenient to introduce initial conditions in an integrator.
 A criterion for good integration in terms of steady-state analysis is as
follows: The low-pass circuit acts as an integrator provided the time
constant of the circuit RC > 15T, where T is the period of the input sine
wave. When RC > 15T, the input sinusoid will be shifted at least by 89.4°
(instead of the ideal 90° shift required for integration) when it is
transmitted through the network.
 An RC integrator converts a square wave into a triangular wave.
Integrators are almost invariably preferred over differentiators in analog
computer applications for the following reasons:

32. Module 2: Attenuators
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Attenuators are resistive networks, which are used to reduce the amplitude of
the input signal. The simple resistor combination of Figure 1.61 (a) would
multiply the input signal by the ratio a = R2/(R1 + R2) independently of the
frequency. If the output of the attenuator is feeding a stage of amplification,
the input capacitance C2 of the amplifier will be the stray capacitance
shunting the resistor R2 of the attenuator and the attenuator will be as shown
in Figure 1.61(b), and the attenuation now is not independent of frequency

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36. UNIT-II: Non linear wave shaping
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Nonlinear wave shaping circuits may be classified as clipping circuits and
clamping circuits.
 A clipping circuit is a circuit which removes the undesired part of the
waveform and transmits only the desired part of the signal which is above
or below some particular reference level, i.e. it is used to select for
transmission that part of an arbitrary waveform which lies above or below
some particular reference.
 Clipping circuits are also called voltage (or current) limiters, amplitude
selectors or slicers.
 Clipping circuits may be single level clippers or two level clippers.
Single level clippers may be series diode clippers with and without
reference or shunt diode clippers with and without reference. Clipping
circuits may use diodes or transistors.
 Clamping circuits may be negative clampers (positive peak clampers)
with and without reference or positive clampers (negative peak clampers)
with and without reference.

37. Diode Characteristics
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The V-I characteristic of a practical diode and idealized diode
approximated by a curve which is shown below. The break point occurs at
Vr, where Vr = 0.2 V for Ge and Vr = 0.6 V for Si. Usually Vr is very small
compared to the reference voltage VR and can be neglected.

38. Clippers
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Typical projects of electronics operate at different electrical signal ranges and
therefore, for these electronic circuits, it is intended to maintain the signals in a
particular range in order to obtain the desired outputs.
Clipper and Clamper are widely used in analog television receivers and FM
transmitters. The variable frequency interference can be removed by using the
clamping method in television receivers, and in FM transmitters, the noise
peaks are limited to a specific value, above which the excessive peaks can be
removed by using the clipping method.
An electronic device that is used to evade the output of a circuit to go
beyond the preset value (voltage level) without varying the remaining
part of the input waveform is called as Clipper circuit.

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1. Series Clippers
Series clippers are again classified into series negative clippers and series
positive clippers which are as follows:
a. Series Negative Clipper
Series Negative Clipper
 The above figure shows a series negative clipper with its output waveforms.
During the positive half cycle the diode (considered as ideal diode) appears in
the forward biased and conducts such that the entire positive half half cycle of
input appears across the resistor connected in parallel as output waveform.
 During the negative half cycle the diode is in reverse biased. No output
appears across the resistor. Thus, it clips the negative half cycle of the input
waveform, and therefore, it is called as a series negative clipper.

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Series Negative Clipper With reference voltage Vr:
Series Negative Clipper With Positive Vr
 During the positive half cycle, the diode start conducting only after its anode voltage
value exceeds the cathode voltage value. Since cathode voltage becomes equal to the
reference voltage, the output that appears across the resistor
Series Negative Clipper With Negative Vr
 During the positive half cycle, the entire input appears as output across the resistor,
and during the negative half cycle, the input appears as output until the input value
will be less than the negative reference voltage, as shown in the figure.

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b. Series Positive Clipper
Series Positive Clipper
During the positive half cycle, diode becomes reverse biased, and no output is
generated across the resistor, and during the negative half cycle, the diode conducts
and the entire input appears as output across the resistor.

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Series Positive Clipper with reference voltage Vr:
Series Positive Clipper with Negative Vr
 During the positive half cycle, the output appears across the resistor as a negative
reference voltage. During the negative half cycle, the output is generated after
reaching a value greater than the negative reference voltage.
Series Positive Clipper with Positive Vr
 During the positive half cycle, the reference voltage appears as an output across
the resistor, and during the negative half cycle, the entire input appears as output
across the resistor.

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2. Shunt Clippers
Shunt clippers are classified into two types: shunt negative clippers and shunt positive
clippers.
a. Shunt Negative Clipper
Shunt Negative Clipper
 Shunt negative clipper is connected as shown in the above figure. During the
positive half cycle, the entire input is the output, and during the negative half cycle, the
diode conducts causing no output to be generated from the input.

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Shunt Negative Clipper with Positive Vr
Shunt Negative Clipper with Positive Vr
 During the positive half cycle, the input is generated as output, and during the
negative half cycle, a positive reference voltage will be the output voltage as shown
above.
Shunt Negative Clipper with Negative Vr
Shunt Negative Clipper with Negative Vr
 During the positive half cycle, the entire input appears as output, and during the
negative half cycle, a reference voltage appears as output as shown in the above
figure.

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b. Shunt Positive Clipper
Shunt Positive Clipper
During the positive half cycle the diode is in conduction mode and no output is
generated; and during the negative half cycle; entire input appears as output as the
diode is in reverse bias as shown in the above figure.

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Shunt Positive Clipper with Negative Vr
Shunt Positive Clipper with Negative Vr
During the positive half cycle, the negative reference voltage connected in series with
the diode appears as output; and during the negative half cycle, the diode conducts until
the input voltage value becomes greater than the negative reference voltage and output
will be generated
Shunt Positive Clipper with Positive Vr
Shunt Positive Clipper with Positive Vr
During the positive half cycle the diode conducts causing the positive reference voltage
appear as output voltage; and, during the negative half cycle, the entire input is
generated as the output as the diode is in reverse biased.

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Positive-Negative Clipper with Reference Voltage Vr
Positive-Negative Clipper with Reference Voltage Vr
 The circuit is connected as shown in the figure with a reference voltage Vr, diodes D1
& D2. During the positive half cycle, the diode the diode D1 conducts causing the
reference voltage connected in series with D1 to appear across the output.
 During the negative cycle, the diode D2 conducts causing the negative reference
voltage connected across the D2 appear as output, as shown in the above figure.

48. Applications of Clippers
Clippers find several applications, such as
They are frequently used for the separation of synchronizing signals from the
composite picture signals.
The excessive noise spikes above a certain level can be limited or clipped in FM
transmitters by using the series clippers.
For the generation of new waveforms or shaping the existing waveform,
clippers are used.
The typical application of diode clipper is for the protection of transistor from
transients, as a freewheeling diode connected in parallel across the inductive
load.
Frequently used half wave rectifier in power supply kits is a typical example of
a clipper. It clips either positive or negative half wave of the input.
Clippers can be used as voltage limiters and amplitude selectors.
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49. MATRUSRI
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Clampers
Working of Clamper Circuit
 The positive or negative peak of a signal can be positioned at the
desired level by using the clamping circuits. As we can shift the
levels of peaks of the signal by using a clamper, hence, it is also
called as level shifter.
 The clamper circuit consists of a capacitor and diode connected in
parallel across the load. The clamper circuit depends on the change
in the time constant of the capacitor.
 The capacitor must be chosen such that, during the conduction of
the diode, the capacitor must be sufficient to charge quickly and
during the non conducting period of diode, the capacitor should not
discharge drastically. The clampers are classified as positive and
negative clampers based on the clamping method.

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1. Negative Clamper
Negative Clamper
During the positive half cycle, the input diode is in forward bias- and as the diode
conducts-capacitor gets charged (up to peak value of input supply). During the
negative half cycle, reverse does not conduct and the output voltage become equal to
the sum of the input voltage and the voltage stored across the capacitor.

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a. Negative Clamper with Positive Vr
Negative Clamper with Positive Vr
 As the positive reference voltage is connected in series with the diode, during the
positive half cycle, even though the diode conducts, the output voltage becomes
equal to the reference voltage; hence, the output is clamped towards the positive
direction.
b. Negative Clamper with Negative Vr
Negative Clamper with Negative Vr
 By inverting the reference voltage directions, the negative reference voltage is
connected in series with the diode as shown in the above figure. During the positive
half cycle, the diode starts conduction before zero, as the cathode has a negative
reference voltage, which is less than that of zero and the anode voltage, and thus,
the waveform is clamped towards the negative direction by the reference voltage
value.

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2. Positive Clamper
Positive Clamper
 It is almost similar to the negative clamper circuit, but the diode is connected in
the opposite direction. During the positive half cycle, the voltage across the output
terminals becomes equal to the sum of the input voltage and capacitor voltage
(considering the capacitor as initially fully charged). During the negative half cycle
of the input, the diode starts conducting and charges the capacitor rapidly to its peak
input value. Thus the waveforms are clamped towards the positive direction as
shown above.

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a. Positive Clamper with Positive Vr
Positive Clamper with Positive Vr
 During the positive half cycle of the input, the diode conducts as initially the supply
voltage is less than the anode positive reference voltage. If once the cathode voltage
is greater than anode voltage then the diode stops conduction. During the negative
half cycle, the diode conducts and charges the capacitor.
b. Positive Clamper with Negative Vr
Positive Clamper with Negative Vr
 During the positive half cycle the diode will be non conducting, such that the
output is equal to capacitor voltage and input voltage. During the negative half
cycle, the diode starts conduction only after the cathode voltage value becomes less
than the anode voltage.

54. Clamping Circuit Theorem
The clamping circuit theorem states that under steady-state
conditions, for any input waveform, the ratio of the area under the
output voltage curve in the forward direction to that in the reverse
direction is equal to the ratio Rf/R. To prove the clamping circuit
theorem, consider a typical steady-state output for the clamping
circuit. The expression for the clamping circuit theorem is:
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Applications of Clampers
Clampers can be used in applications:
 The complex transmitter and receiver circuitry of television clamper is
used as a base line stabilizer to define sections of the luminance signals to
preset levels.
 Clampers are also called as direct current restorers as they clamp the wave
forms to a fixed DC potential.
 These are frequently used in test equipment, sonar and radar systems.
 For the protection of the amplifiers from large errant signals clampers are
used.
 Clampers can be used for removing the distortions.
 For improving the overdrive recovery time clampers are used.
 Clampers can be used as voltage doublers or voltage multipliers.

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UNIT-III: Multivibrators
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INTRODUCTION:
A multivibrator is used to implement simple two-state systems such as
oscillators, timers and flip-flops.
 Three types:
Astable – neither state is stable.
Applications: oscillator, etc.
Monostable - one of the states is stable, but the other is not;
Applications: timer, etc.
Bistable – it remains in either state indefinitely.
Applications: flip-flop, etc.

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OUTCOMES:
To study the principle of operation of the multivibrators.
To study the applications of multivibrators.
To realize the need for a commutating condenser in a monostable
multivibrator and bistable multivibrator.
To study the principle of operation of Time base generators
To study the features of the Time base signal.
To study the principle of operation of Miller Time base
To study the principle of operation of Bootstrap Time base generator
To study the principle of operation of UJT saw tooth generator.
To study the principle of operation of time base generators using Op-
Amps.

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MODULE-I: Multivibrators
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CONTENTS:
 Bistable multivibrator
 Monostable multivibrator
 Astable multivibrator
 Schmitt Trigger
OUTCOMES:
To study the principle of operation of the multivibrators.
To study the applications of multivibrators.
To realize the need for a commutating condenser in a monostable
multivibrator and bistable multivibrator.

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Astable Multivibrator

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Basic mode of operation

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Multivibrator Frequency

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Monostable Multivibrator

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Bistable Multivibrator

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Schmitt Trigger
Circuit Output Waveforms

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 Advantages
The advantages of Schmitt trigger circuit are
•Perfect logic levels are maintained.
•It helps avoiding Meta-stability.
•Preferred over normal comparators for its pulse conditioning.
 Disadvantages
The main disadvantages of a Schmitt trigger are
•If the input is slow, the output will be slower.
•If the input is noisy, the output will be noisier.
 Applications of Schmitt trigger
Schmitt trigger circuits are used as Amplitude Comparator and Squaring
Circuit. They are also used in Pulse conditioning and sharpening circuits.

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Module 2: Time Base Generators
A time-base generator is an electronic circuit which generates an output
voltage or current waveform, a portion of which varies linearly with time.
Ideally the output waveform should be a ramp.
Time-base generators may be voltage time-base generators or current
time-base generators.
A voltage time-base generator is one that provides an output voltage
waveform, a portion of which exhibits a linear variation with respect to
time. A current time-base generator is one that provides an output current
waveform, a portion of which exhibits a linear variation with respect to
time.
There are many important applications of time-base generators, such as in
CROs, television and radar displays, in precise time measurements, and in
time modulation.
 Since this waveform is used to sweep the electron beam horizontally
across the screen it is called the sweep voltage and the time-base
generators are called the sweep circuits.

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GENERAL FEATURES OF A TIME-BASE SIGNAL
Precisely linear sweep signals are difficult to generate by time-base
generators and moreover nominally linear sweep signals may be
distorted when transmitted through a coupling network.
The deviation from linearity is expressed in three most important ways:
1 . The slope or sweep speed error, es
2. The displacement error, ed
3. The transmission error, et

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1. The Slope or Sweep Speed Error (es):
A Sweep voltage must increase linearly with time. The rate of change of
sweep voltage with time must be constant. This deviation from linearity
is defined as Slope Speed Error or Sweep Speed Error.

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2. The Transmission Error (et):
When a sweep signal passes through a high pass circuit, the output
gets deviated from the input as shown below.
This deviation is expressed as transmission error.
Where V’s is the input and Vs is the output at the end of the
sweep i.e. at t = Ts.

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3. The Displacement Error (ed)
An important criterion of linearity is the maximum difference between the
actual sweep voltage and the linear sweep which passes through the
beginning and end points of the actual sweep.
This can be understood from the following figure.
The displacement error ed is defined as

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Relation between three errors:
If the deviation from linearity is very small and the sweep voltage may
be approximated by the sum of linear and quadratic terms in t, then the
above three errors are related as

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METHODS OF GENERATING A TIME-BASE WAVEFORM
 Exponential charging. In this method a capacitor is charged from a supply
voltage through a resistor to a voltage which is small compared with the supply
voltage.
 Constant current charging. In this method a capacitor is charged linearly from a
constant current source. Since the charging current is constant the voltage across
the capacitor increases linearly.
 The Miller circuit. In this method an operational integrator is used to convert
an input step voltage into a ramp waveform.
 The Phantastron circuit. In this method a pulse input is converted into a ramp.
This is a version of the Miller circuit.
 The bootstrap circuit. In this method a capacitor is charged linearly by a
constant current which is obtained by maintaining a constant voltage across a
fixed resistor in series with the capacitor.
 Compensating networks. In this method a compensating circuit is introduced to
improve the linearity of the basic Miller and bootstrap time-base generators.
 An inductor circuit. In this method an RLC series circuit is used. Since an
inductor does not allow the current passing through it to change instantaneously,
the current through the capacitor more or less remains constant and hence a more
linear sweep is obtained.

76. MATRUSRI
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Bootstrap Time Base Generator
A bootstrap sweep generator is a time base generator circuit whose output
is fed back to the input through the feedback. This will increase or decrease
the input impedance of the circuit. This process of bootstrapping is used to
achieve constant charging current.
Advantage
The main advantage of this boot strap ramp generator is that the
output voltage ramp is very linear and the ramp amplitude reaches
the supply voltage level.

77. MATRUSRI
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Miller Sweep Generator
The transistor Miller time base generator circuit is the popular Miller
integrator circuit that produces a sweep waveform. This is mostly used
in horizontal deflection circuits.
Applications:
Miller sweep circuits are the most commonly used integrator circuit in
many devices. It is a widely used saw tooth generator.

78. MATRUSRI
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Unijunction Transistor
Unijunction Transistor is such a transistor that has a single PN
junction, but still not a diode. Unijunction Transistor, or
simply UJT has an emitter and two bases, unlike a normal transistor.
This component is especially famous for its negative resistance
property and also for its application as a relaxation oscillator.

79. MATRUSRI
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Circuit diagram Output Waveform
Applications of UJT
UJTs are most prominently used as relaxation oscillators. They are also used in Phase
Control Circuits. In addition, UJTs are widely used to provide clock for digital
circuits, timing control for various devices, controlled firing in thyristors, and sync
pulsed for horizontal deflection circuits in CRO.

80. Digital Logic families
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81. Unit V- Integrated Circuits
 What is an Integrated Circuit?
 Where do you use an Integrated Circuit?
 Why do you prefer an Integrated Circuit to the circuits
made by interconnecting discrete components?
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82. Def: The “Integrated Circuit “ or IC is a miniature,
low cost electronic circuit consisting of active and
passive components that are irreparably joined
together on a single crystal chip of silicon.
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83. Applications of an Integrated Circuit
 Communication
 Control
 Instrumentation
 Computer
 Electronics
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84.  Small size
 Low cost
 Less weight
 Low supply voltages
 Low power consumption
 Highly reliable
 Matched devices
 Fast speed
Advantages:
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85. Classification
 Digital ICs
 Linear ICs
Integrated circuits
Pn junction
isolation
Hybrid circuits
Dielectric
isolation
Monolithic circuits
Bipolar Uni polar
MOSFET JFET
Classification of ICs
Thick
&Thin film
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86. Chip size and Complexity
 ULSI (more than one million active devices are integrated on single
chip)
 Invention of Transistor (Ge) - 1947
 Development of Silicon - 1955-1959
 Silicon Planar Technology - 1959
 First ICs, SSI (3- 30gates/chip) - 1960
 MSI ( 30-300 gates/chip) - 1965-1970
 LSI ( 300-3000 gates/chip) -1970-1975
 VLSI (More than 3k gates/chip) - 1975
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87. SSI MSI LSI VLSI ULSI
< 100 active 100-1000 1000- >100000 Over 1
devices active 100000 active million
devices active devices active
devices devices
Integrated BJT’s and MOSFETS 8bit, 16bit Pentium
resistors, Enhanced Microproces Microproces
diodes & MOSFETS sors sors
BJT’s
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88. Selection of IC Package
Type Criteria
Metal can
package
1. Heat dissipation is important
2. For high power applications like power
amplifiers, voltage regulators etc.
DIP 1. For experimental or bread boarding
purposes as easy to mount
2. If bending or soldering of the leads is
not required
3. Suitable for printed circuit boards as
lead spacing is more
Flat pack 1. More reliability is required
2. Light in weight
3. Suited for airborne applications
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89. Factors affecting selection of IC package
 Relative cost
 Reliability
 Weight of the package
 Ease of fabrication
 Power to be dissipated
 Need of external heat sink
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90. 1. Military temperature range : -55o C to +125o C (-55o C to +85o C)
2. Industrial temperature range : -20o C to +85o C (-40o C to +85o C )
3. Commercial temperature range: 0o C to +70o C (0o C to +75o C )
Temperature Ranges
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91. The metal can (TO)
Package
The Dual-in-Line (DIP)
Package
The Flat Package
Packages
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92. Manufacturer’s Designation for Linear ICs
 Fairchild
 National Semiconductor
 Motorola
 RCA
- µA, µAF
- LM,LH,LF,TBA
- MC,MFC
- CA,CD
 Texas Instruments - SN
 Signetics - N/S,NE/SE
 Burr- Brown - BB
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93. Fairchild’s original µA741 is also manufactured by
other manufactures as follows
 National Semiconductor - LM741
 Motorola
 RCA
 Texas Instruments
 Signetics
- MC1741
- CA3741
- SN52741
- N5741
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94.  741 Military grade op-amp
 741C Commercial grade op-amp
 741A Improved version of 741
 741E Improved version of 741C
 741S Military grade op-amp with higher slew rate
 741SC Commercial grade op-amp with higher slew rate
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95. Overview
• Integration, Moore’s law
• Early families (DL, RTL)
• TTL
• Evolution of TTL family
• ECL
• CMOS family and its evolution
• Overview
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96. Integration Levels
• Gate/transistor ratio is roughly 1/10
– SSI
– MSI
– LSI
– VLSI
– ULSI
– GSI
< 12 gates/chip
< 100 gates/chip
…1K gates/chip
…10K gates/chip
…100K gates/chip
…1Meg gates/chip
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97. Moore’s law
• A prediction made by Moore (a co-founder of Intel) in
1965: “… a number of transistors to double every 2
years.”
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98. In the beginning…
=
Diode Logic (DL)
•simplest; does not
scale
•NOT not possible
(need an active
elements)-
Resistor Transistor
Logic (RTL)
•replace diode switch
with a transistor switch
•can be cascaded
•large power draw
=
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99. was…
=
Diode-Transistor Logic (DTL)
•essentially diode logic with transistor
amplification
•reduced power consumption
•faster than RTL
DL AND gate Saturating inverter
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100. VOH(min) – The minimum voltage level at an output in the logical “1” state under
defined load conditions
VOL(max) – The maximum voltage level at an output in the logical “0” state under
defined load conditions
VIH(min) – The minimum voltage required at an input to be recognized as “1”
logical state
VIL(max) – The maximum voltage required at an input that still will be recognized
as “0” logical state
Logic families: V levels
VIH
VOH VOL VIL
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101. IOH – Current flowing into an output in the logical “1” state under specified load
conditions
IOL – Current flowing into an output in the logical “0” state under specified load
conditions
IIH – Current flowing into an input when a specified HI level is applied to that
input IIL – Current flowing into an input when a specified LO level is applied to
that input
Logic families: I requirements
IOH
VIH
VOH VOL VIL
IIH IOL IIL
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102. Fanout: the maximum number of logic inputs (of the
same logic family) that an output can drive reliably
Logic families: fanout
DC fanout = min(
IOH ),
IOL
IIH IL I
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103. Logic families: propagation delay
TPD,HL TPD,LH
TPD,HL – input-to-output
propagation delay from HI
to LO output TPD,LH – input-
to-output propagation delay
from LO to HI output
Speed-power
product: TPD  Pavg
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104. Logic families: noise margin
HI state noise margin:
VNH = VOH(min) – VIH(min)
LO state noise margin:
VNL = VIL(max) – VOL(max)
Noise margin:
VN = min(VNH,VNL)
VNH
VNL
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105. TTL
2-input NAND
Bipolar Transistor-Transistor Logic (TTL)
•first introduced by in 1964 (Texas Instruments)
•TTL has shaped digital technology in many ways
•Standard TTL family (e.g. 7400) is obsolete
•Newer TTL families still used (e.g. 74ALS00)
Distinct features
•Multi-emitter transistors
•Totem-pole transistor
arrangement
•Open LTspice example:
TTL NAND…
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106. TTL evolution
Schottky series (74LS00) TTL
•A major slowdown factor in BJTs is due to
transistors going in/out of saturation
•Shottky diode has a lower forward bias (0.25V)
•When BC junction would become forward biased,
the Schottky diode bypasses the current
preventing the transistor from going into saturation
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107. TTL family evolution
Legacy: don’t use in
new designs
Widely used today
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108. ECL
Emitter-Coupled Logic (ECL)
•PROS: Fastest logic family available (~1ns)
•CONS: low noise margin and high power
dissipation
•Operated in emitter coupled geometry (recall
differential amplifier or emitter-follower),
transistors are biased and operate near their Q-
point (never near saturation!)
•Logic levels. “0”: –1.7V. “1”: –0.8V
•Such strange logic levels require extra effort
when interfacing to TTL/CMOS logic families.
•Open LTspice example: ECL inverter…
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109. CMOS
Complimentary MOS (CMOS)
•Other variants: NMOS, PMOS (obsolete)
•Very low static power consumption
•Scaling capabilities (large integration all MOS)
•Full swing: rail-to-rail output
•Things to watch out for:
– don’t leave inputs floating (in TTL these will
float
to HI, in CMOS you get undefined behaviour)
– susceptible to electrostatic damage (finger
of death)
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110. Life-cycle
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