Integrated Circuits.ppt

McGraw-Hill © 2008 The McGraw-Hill Companies Inc. All rights reserved.

ElectronicsElectronics

Principles & ApplicationsPrinciples & ApplicationsSeventh EditionSeventh Edition

Chapter 13Integrated Circuits(student version)

Charles A. Schuler



• IC fabrication• The 555 Timer• Analog ICs• Mixed-signal ICs• Troubleshooting

INTRODUCTION


Dear Student:

This presentation is arranged in segments. Each segmentis preceded by a Concept Preview slide and is followed by aConcept Review slide. When you reach a Concept Reviewslide, you can return to the beginning of that segment byclicking on the Repeat Segment button. This will allow youto 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 makingICs 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


Silicon substrate

Start with a silicon substrateCoat with silicon dioxideCoat with photoresistCover with photomaskExpose with lightDevelopEtchDiffusion

Dopant

A P-N junction has been formed.


Batch processing

Each wafer will yield dozens of ICs (or more).

Wafer


Probetest


During the probe test, the defective ICs are marked.

After the wafer is separated,the defective ICs are discarded.


Using photolithography to form an NPN BJT

1. P- type substrate

2. N+ diffusion layer

3. N epitaxial layer

4. Silicon dioxide layer

5. Expose and etch

6. Boron diffusion

7. Silicon dioxide layer

8. Expose and etch

9. Boron base diffusion

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

Collector contact Emitter contact

Base contact


IC fabrication quiz

The base process in making monolithic ICsis _______________. photolithography

The wafer is coated with photoresist andexposed through a _________. photomask

Etching produces windows through whichimpurities are ________. diffused

The electrical performance of each chip on thewafer is checked during the ____ test. probe

Individual sections are electrically connectedwith 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.


5 k

R

S Q

Q5 k

5 k

Gnd1

Out

3

+VCC8Discharge

Threshold

Control

Trigger

7

6

5

2

555555

Reset4

UTP2/3 VCC

LTP1/3 VCC

A popular timer IC


SRQ

Q

R

S Q

Q

How the RS flip-flop in the 555 timer works:

Once set, the Q output remainshigh until the flip-flop is reset.

Outputs are inopposite states.


1

3

+VCC

7

6

2

8One-shot operation

R

C

1/3 VCC

The input trigger resets the flip-flop and C then chargesuntil the top comparator trips and sets the flip-flop.

SR

input triggeroutput pulse

Dischargetransistor


+ VCC

555

48

7

6

1

3

2

R

C

t = 1.1RCOutput pulse

Trigger1/3 VCC

The external components determine the output pulse width.


1

3

+VCC

7

6

2

8

Free-running orastable operationRB

C

RA

SR

2/3 VCC

1/3 VCC

C charges through RA+ RB

and discharges through RB.


+ VCC

555

48

7

6

1

3

2

RA

C

Astablemode duty

cycle > 50%

RB

f =1.45

(RA + 2RB)C

Duty Cycle = RA + 2RB

x 100%RA + RB


+ VCC

555

48

7

6

1

3

2

RA

C

Astablemode duty

cycle < 50%

RB

f =1.45

(RA + RB)C

RADuty Cycle =

RA + RB

x 100%

C chargesthrough RA

and dischargesthrough RB.


+ VCC

555

48

6

1

3

2

R

C

Trigger

Time-delaymode

Time delay = 1.1 RCOutput


Pulse-position modulation

Modulation


555 timer quiz

The voltage of the trigger signal must beless than 1/3 _________. VCC

The threshold and trigger comparatorscontrol the ___________. RS flip-flop

The Q output of the RS flip-flop controlsthe __________ transistor. discharge

In one-shot mode, the external R and C setthe _______ of the output pulse. width

In astable mode, the 555 timer acts as an____________. 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 load.

V+

V-Out

VIN+

VIN-

MuteGnd

11-lead TO220plastic package

0.1% THD20 Hz – 20 kHz

95 dB SNR

Load, voltageand temperature

protected

100 W peakoutput


Mixed signal ICs contain or use bothdigital and analog circuit functions.

1

2

3 4

5

6

GND

U/D CS

W

HVCC

MAX5468

This Maxim digital potentiometer is an example. Itprovides 32 output levels from pin 5 for volumecontrol applications. It is adjusted by applying

digital pulses to pin 3. Pin 4, along with pin 3, selectseither a volume up or a volume down mode.


ErrorAmplifier

Phasedetector

LPF

VCO

Phase-locked loops are mixed signal ICs.

The phase detectoris usually digital.


ErrorAmplifier

Phasedetector

LPF

VCO

Phase-locked loop

In

In

VCO

The VCO locks onto the input phase.


ErrorAmplifier

Phasedetector

LPF

VCO

In

The VCO also locks onto the input frequency.

Out

Ou

tpu

t vo

ltag

e

Input frequency

Lock range


ErrorAmplifier

Phasedetector

LPF

VCO

In

PLLs can serve as FM detectors.

Out


ErrorAmplifier

Phasedetector

LPF

VCO

fREF

PLL frequency synthesizer

fOUT

Digitaldivide by N fOUT = N(fREF)


A sample and hold can be a separate circuitor part of an analog to digital converter.

hold capacitoranalog input

clock

switch

A/D occurs when signalvoltage is not changing

to A/D


4-bit D/A converter

Vout

R R

2R

4R

8R

Output states = 2N = 24 = 16

N = 4

5 V8

5 V0 V

-9.375 V


1 ms-10

0

time

volt

s

0

Switched capacitor voltage inverter


1 ms0

20

time

volt

s

0

Switched capacitor voltage doubler


Conventional and switched capacitor integrators

1 ms

10

time

volt

s

00

C1

C2

C

RSlope of Vout = -Vin x

RC

1

Slope of Vout = -Vin x C2

C1x fclock


Mixed signal IC quiz

When a PLL is locked, the VCO tracks theinput _________. signal

PLLs can be used as FM _________.detectors

With a divide by N, a PLL serves as afrequency _____________. synthesizer

The output of a 6-bit D/A converter has_______ possible output levels. 64

The output slope of a switched capacitor_______ depends on the clock frequency.

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

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Integrated Circuits.ppt