1. Principles & Applications
Electronics
Principles & Applications
Sixth Edition
Charles A. Schuler
Chapter 13
Integrated Circuits
© Glencoe/McGraw-Hill

2. INTRODUCTION IC Fabrication The 555 Timer Analog ICs Mixed-signal ICs
Troubleshooting

3. 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

4. Dopant
Silicon substrate
Coat with photoresist
Expose with light
Cover with photomask
Develop
Start with a silicon substrate
Coat with silicon dioxide
Etch
Diffusion
A P-N junction has been formed.

5. Wafer
Batch Processing
Each wafer will yield dozens of ICs (or more).

6. Probe
Test

7. After the wafer is separated, the defective ICs are discarded.
During the probe test, the defective ICs are marked.
After the wafer is separated,
the defective ICs are discarded.

8. Using photolithography to form an NPN BJT
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

9. 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

10. 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

11. 555 +VCC 8 Discharge 7 5 kW Threshold 6 2/3 VCC S Q Control 5 kW 3 5 R
A popular timer IC
Discharge 7
555
5 kW
Threshold 6
UTP
2/3 VCC S Q
Control
5 kW 3 5 R Q
1/3 VCC
Out
LTP
Trigger 2
5 kW 1
Gnd 4
Reset

12. Once set, the Q output remains high until the flip-flop is reset.
How the RS flip-flop in the 555 timer works: S R Q Q S Q
Outputs are in
opposite states. R Q
Once set, the Q output remains
high until the flip-flop is reset.

13. One-shot Operation +VCC 8 R 7 6 C 3 2 1/3 VCC 1
Discharge
transistor R 7 6 C S 3 R
output pulse
input trigger 2
1/3 VCC 1
The input trigger resets the flip-flop and C then charges
until the top comparator trips and sets the flip-flop.

14. R 8 4 7 C 555 6 3 t = 1.1RC Output pulse 2 Trigger 1
+ VCC R 8 4 7 C
555 6 3
t = 1.1RC
Output pulse 2
Trigger
1/3 VCC 1
The external components determine the output pulse width.

15. C charges through RA+ RB and discharges through RB.
+VCC
C charges through RA+ RB
and discharges through RB. 8
Free-running or
Astable Operation 7 RB 6 S 3 R 2 C 1
2/3 VCC
1/3 VCC

16. Astable Mode Duty Cycle > 50%
+ VCC RA 8 4 7 RB
555 6 3 2 C 1
Duty Cycle =
RA + 2RB
x 100%
RA + RB
f =
1.45
(RA + 2RB)C

17. Astable Mode Duty Cycle < 50%
+ VCC
Astable
Mode Duty
Cycle < 50%
C charges
through RA
and discharges
through RB. RA 8 4 7 RB
555 3 6 2 C 1 RA
Duty Cycle =
RA + RB
x 100%
f =
1.45
(RA + RB)C

18. Time-delay Mode R 8 4 6 555 3 2 1 C Trigger Time delay = 1.1 RC Output
+ VCC
Time-delay
Mode R 8 4 6
555 3 2 1 C
Trigger
Time delay = 1.1 RC
Output

19. Pulse-position Modulation

20. 555 Timer Quiz
The voltage of the trigger signal must be less than 1/3 __________.
VCC
The threshold and trigger comparators
control the __________.
RS flip-flop
The Q output of the RS flip-flop controls the __________ transistor.
discharge
In one-shot mode, the external R and C set the __________ of the output pulse.
width
In astable mode, the 555 timer acts as an __________.
oscillator

21. Analog ICs include: Linear voltage regulators Differential amps
High-speed amps
Op amps
RF and IF amps
Modulators and mixers
Demodulators
Power amps

22. The LM3876 delivers up to 56W of audio output power to an 8 W load.
VIN+
VIN-
Mute
Gnd
11-lead TO220
plastic package
0.1% THD
20 Hz – 20 kHz
95 dB SNR
Load, voltage
and temperature
protected
100 W peak
output

23. Mixed signal ICs contain or use both
digital and analog circuit functions. 1 2 3 4 5 6
GND
U/D CS W H
VCC
MAX5468
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.

24. Phase-locked loops are mixed signal ICs.
Error
Amplifier
Phase
Detector
LPF
VCO
The phase detector
is usually digital.

25. Phase-locked Loop In In VCO Phase Error LPF Detector Amplifier VCO
The VCO locks onto the input phase. In
VCO

26. The VCO also locks onto the input frequency.
Error
Amplifier
Out In
Phase
Detector
LPF
VCO
Output voltage
Lock range
Input frequency

27. PLLs can serve as FM detectors.
Error
Amplifier
Out In
Phase
Detector
LPF
VCO

28. PLL Frequency Synthesizer
Error
Amplifier
fREF
Phase
Detector
LPF
Digital
divide by N
fOUT = N(fREF)
VCO
fOUT

29. 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
to A/D
hold capacitor
analog input
clock

30. 4-bit D/A Converter Output states = 2N = 24 = 16 5 V 5 V 8 R R 2R Vout

31. Switched Capacitor Voltage Inverter
1 ms
-10
time
volts

32. Switched Capacitor Voltage Doubler
1 ms 20
time
volts

33. Conventional and Switched Capacitor Integrators
Slope of Vout
= -Vin x RC 1 R C2 C1
1 ms 10
time
volts
Slope of Vout
= -Vin x C2
C1x fclock

34. 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 __________.
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

35. 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.

36. REVIEW IC Fabrication The 555 Timer Analog ICs Mixed-signal ICs
Troubleshooting