Integrated Circuits

1
Integrated Circuits the 555
2
Integrated Circuits

• History
• tubes and valves
• transistor - 1947 Bell Labs, Holmdel, NJ

3
IC Families

• How logic gates are configured
• TTL
• CMOS

4
IC Families

• TTL - Transistor-Transistor Logic
• CMOS - Complementary Metal Oxide Semiconductor

5
IC Families

• TTL - Transistor-Transistor Logic
• 74xx designation, i.e., 7447,7490, etc. digital
  devices
• Requires 5 volt supply (max. 5.5 volts)
• moderately high current draw
• Includes 74Lxx 74LSxx designations (74L47,
  74LS47) that have significantly lower current
  requirements

6
IC Families

• CMOS - Complementary Metal-Oxide Semiconductor
• 4000 designation, i.e., 4001, 4511, 4517, etc.
• Works within a range of voltage 3-15 volts
• Low current requirements
• slightly higher cost than TTL
• very sensitive to static charges (it ruins them)

7
555

• Introduced in 1972
• Can accurately time from 0.0000011 seconds to
  11,000 seconds (just over 3 hours)
• Uses external capacitor and 1 or 2 resistors to
  control timing
• Output is always a digital signal (on-off square
  wave)
• Contains 28 transistors, 12 resistors
• Requires 4.5 - 18 volts
• Will switch 200mA

8
555 Timer
555
1
8
DIP chip Dual In-Line Pins
2
7
3
6
4
5
top view
9
555 Timer
555
1
8
Ground (-)
5 to 15VDC
2
7
3
6
4
5
top view
10
555 Timer

• High state output is always 1.7V less than
  supply
• Output is 7.3V _at_ 9V supply

555
1
8
Ground (-)
5 to 15VDC
2
7
3
6
Output
4
5
top view
11
555

• Monostable timing
• One shot timing
• One stable state (off)
• Switches on for duration of time then goes back
  to stable (off) state

12
555

• Astable timing
• No stable state (keeps flip-flopping between
  states)
• On time called mark
• Off time called space
• Mark-space timing can be adjusted with external
  capacitor and two resistors

13
Monostable circuit
9VDC
R1 470K
555
7
R2 1K
8
6
4
2
3
1
LED
C1 47mf
R3 330
14
Monostable circuit
15
Monostable circuit
9VDC
Timing Control Components
R1 470K
555
7
R2 1K
8
6
4
2
3
1
LED
C1 47mf
R3 330
16
Monostable circuit
9VDC
Output Components
R1 470K
555
7
R2 1K
8
6
4
2
3
1
LED
C1 47mf
R3 330
17
Monostable circuit
9VDC
R1 470K
LED
555
7
R2 1K
8
R3 330
6
4
2
3
1
Note LED polarity
C1 47mf
18
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