Electronics
Principles & Applications
Sixth Edition
Charles A. Schuler
Chapter 13
Integrated Circuits
(student version)
©2003
Glencoe/McGraw-Hill
INTRODUCTION
• IC Fabrication
• The 555 Timer
• Analog ICs
• Mixed-signal ICs
• Troubleshooting
Dear Student:
This presentation is arranged in segments.
Each segment is preceded by a Concept
Preview slide and is followed by a Concept
Review slide. When you reach a Concept
Review slide, you can return to the
beginning of that segment by clicking on the
Repeat Segment button. This will allow you
to view that segment again, if you want to.
Concept Preview
• Photolithography is the base process used in
making monolithic integrated circuits.
• Impurities are diffused into the substrate to
form PN junctions.
• ICs are batch processed. One wafer will yield
many devices.
• A probe test identifies defective ICs before the
wafer is cut apart.
• An aluminum metalization layer interconnects
the various IC components.
The base process in making
ICs is photolithography.
• Silicon wafer (the substrate) oxidized on
its surface
• Coated with photoresist
• Covered with a photomask
• Exposed to light and developed
• Etched to expose the substrate
• Impurity diffusion into the substrate
• Repeat eight to twenty times
Dopant
Silicon substrate
Start
Coat
with
silicon
awith
silicon
dioxide
substrate
Coat
with
photoresist
Develop
Cover
with
photomask
Expose
light
A P-N
junction
has
been
formed.
Etch
Diffusion
Wafer
Batch Processing
Each wafer will yield dozens of ICs (or more).
Probe
Test
During the probe test, the
defective ICs are marked.
After the wafer is separated,
the defective ICs are discarded.
1. P- type substrate
6. Boron diffusion
2. N+ diffusion layer
7. Silicon dioxide layer
3. N epitaxial layer
8. Expose and etch
4. Silicon dioxide layer
9. Boron base diffusion
5. Expose and etch
10. Emitter diffusion
Using photolithography to form an NPN BJT
11. Coat, expose and etch
12. Aluminum metalization layer
13. Coat, expose and etch away extra aluminum
Base contact
Collector contact
Emitter contact
Using photolithography to form an NPN BJT
IC Fabrication Quiz
The base process in making
monolithic Ics is __________.
photolithography
The wafer is coated with photoresist
and exposed through a __________.
photomask
Etching produces windows through
which impurities are __________.
diffused
The electrical performance of each
chip on the wafer is checked during
the __________ test.
probe
Individual sections are electrically
connected with a film of __________.
aluminum
Concept Review
• Photolithography is the base process used in
making monolithic integrated circuits.
• Impurities are diffused into the substrate to
form PN junctions.
• ICs are batch processed. One wafer will yield
many devices.
• A probe test identifies defective ICs before the
wafer is cut apart.
• An aluminum metalization layer interconnects
the various IC components.
Repeat Segment
Concept Preview
• The 555 timer IC has two comparators, a
discharge transistor and a digital output.
• One-shot operation provides an output pulse
width controlled by an external resistor and
capacitor.
• Astable operation provides a continuous
rectangular waveform at the output.
• Time-delay operation provides an output delay
that is RC controlled.
• Pulse position modulation uses an external
signal to control the comparator trip points.
8 +VCC
Discharge
7
5 kW
Threshold
UTP
S Q
5
1/3 VCC
Trigger
555
6
2/3 VCC
Control
A popular timer IC
5 kW
RQ
Out
LTP
2
5 kW
1 Gnd
3
4 Reset
How the RS flip-flop in the 555 timer works:
S
R
Q
Q
S Q
RQ
Outputs are in
opposite states.
Once set, the Q output remains
high until the flip-flop is reset.
+VCC
8
R
7
C
6
Discharge
transistor
S
R
3
output pulse
input trigger
1/3 VCC
One-shot Operation
2
1
The input trigger resets the flip-flop and C then charges
until the top comparator trips and sets the flip-flop.
+ VCC
R
C
8
7
6
555
2
1/3 VCC
4
3
1
Trigger
t = 1.1RC
Output pulse
The external components determine the output pulse width.
RA
C charges through RA+ RB
and discharges through RB.
+VCC
8
Free-running or
Astable Operation
7
RB
6
S
R
2
C
1
2/3 VCC
1/3 VCC
3
+ VCC
RA
RB
C
8
7
6
2
4
555
1
RA + RB
x 100%
Duty Cycle =
RA + 2RB
1.45
f =
(RA + 2RB)C
Astable
Mode Duty
Cycle > 50%
3
+ VCC
C charges
RA
through RA
and discharges
through RB.
RB
C
8
7
6
2
4
555
Astable
Mode Duty
Cycle < 50%
3
1
RA
x 100%
Duty Cycle =
RA + RB
1.45
f =
(RA + RB)C
+ VCC
R
8
6
2
C
4
555
Time-delay
Mode
3
1
Trigger
Output
Time delay = 1.1 RC
Pulse-position Modulation
Modulation
555 Timer Quiz
The voltage of the trigger signal
must be less than 1/3 __________.
The threshold and trigger comparators
control the __________.
The Q output of the RS flip-flop
controls the __________ transistor.
In one-shot mode, the external R and C
set the __________ of the output pulse.
In astable mode, the 555 timer acts as
an __________.
VCC
RS flip-flop
discharge
width
oscillator
Concept Review
• The 555 timer IC has two comparators, a
discharge transistor and a digital output.
• One-shot operation provides an output pulse
width controlled by an external resistor and
capacitor.
• Astable operation provides a continuous
rectangular waveform at the output.
• Time-delay operation provides an output delay
that is RC controlled.
• Pulse position modulation uses an external
signal to control the comparator trip points.
Repeat Segment
Concept Preview
• There are three IC categories: analog, digital
and mixed signal.
• The most widely-applied analog ICs are
amplifiers and voltage regulators.
• Phase locked loops can be used for FM
detection and for frequency synthesis.
• A sample and hold circuit is usually required
for analog to digital conversion.
• The number of bits sets the output resolution
for digital to analog converters.
• Switched capacitor ICs can provide voltage
conversion and integration.
Analog ICs include:
•
•
•
•
•
•
•
•
Linear voltage regulators
Differential amps
High-speed amps
Op amps
RF and IF amps
Modulators and mixers
Demodulators
Power amps
The LM3876 delivers up to 56W of
audio output power to an 8 W load.
11-lead TO220
plastic package
0.1% THD
20 Hz – 20 kHz
95 dB SNR
Load, voltage
and temperature
protected
100 W peak
output
VIN+
V+
VINOut
V-
Mute
Gnd
Mixed signal ICs contain or use both
digital and analog circuit functions.
VCC 1
6 H
GND 2
5 W
U/D 3 MAX5468
4 CS
This Maxim digital potentiometer is an example.
It provides 32 output levels from pin 5 for volume
control applications. It is adjusted by applying
digital pulses to pin 3. Pin 4, along with pin 3,
selects either a volume up or a volume down mode.
Phase-locked loops are mixed signal ICs.
Phase
Detector
LPF
Error
Amplifier
VCO
The phase detector
is usually digital.
Phase-locked Loop
In
Phase
Detector
LPF
Error
Amplifier
VCO
The VCO locks onto the input phase.
In
VCO
The VCO also locks onto the input frequency.
Phase
Detector
LPF
Error
Amplifier
VCO
Output voltage
In
Lock range
Input frequency
Out
PLLs can serve as FM detectors.
In
Phase
Detector
VCO
LPF
Error
Amplifier
Out
PLL Frequency Synthesizer
fREF
Phase
Detector
LPF
Digital
divide by N
Error
Amplifier
fOUT = N(fREF)
VCO
fOUT
A sample and hold can be a separate circuit
or part of an analog to digital converter.
A/D occurs when signal
voltage is not changing
switch
analog input
to A/D
hold capacitor
clock
4-bit D/A Converter
Output states = 2N = 24 = 16
0V
5V
8
5V
R
R
2R
4R
8R
N=4
Vout
-9.375 V
Switched Capacitor Voltage Inverter
volts
0
-10
0
time
1 ms
Switched Capacitor Voltage Doubler
volts
20
0
0
time
1 ms
Conventional and Switched Capacitor Integrators
C
Slope of Vout = -Vin x
R
1
RC
C2
10
volts
C1
Slope of Vout = -Vin x
C1x fclock 0 0
C2
time
1 ms
Mixed Signal IC Quiz
When a PLL is locked, the VCO tracks
the input __________.
signal
PLLs can be used as FM __________.
detectors
With a divide by N, a PLL serves as
a frequency __________.
The output of a 6-bit D/A converter
has __________ possible output levels.
The output slope of a switched
capacitor __________ depends on the
clock frequency.
synthesizer
64
integrator
Troubleshooting
• Be sure to take a system point of view.
• Is there any software involved?
• Supply voltages may be critical.
• Waveform analysis is often used.
• Check clock frequency.
Concept Review
• There are three IC categories: analog, digital
and mixed signal.
• The most widely-applied analog ICs are
amplifiers and voltage regulators.
• Phase locked loops can be used for FM
detection and for frequency synthesis.
• A sample and hold circuit is usually required
for analog to digital conversion.
• The number of bits sets the output resolution
for digital to analog converters.
• Switched capacitor ICs can provide voltage
conversion and integration.
Repeat Segment
REVIEW
• IC Fabrication
• The 555 Timer
• Analog ICs
• Mixed-signal ICs
• Troubleshooting