MC74HC4020A_11 Просмотр технического описания (PDF) - ON Semiconductor

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Компоненты Описание

производитель

MC74HC4020A_11

14-Stage Binary Ripple Counter

ON Semiconductor 

Clock

Reset

Q4

Q5

Q6

Q7

Q8

Q9

Q10

Q12

Q13

Q14

MC74HC4020A

12

4

8

16

32

64 128 256 512 1024 2048 4096 8192 16384

Figure 8. Timing Diagram

APPLICATIONS INFORMATION

Time−Base Generator

A 60Hz sinewave obtained through a 1.0 Megohm resistor

connected directly to a standard 120 Vac power line is

applied to the input of the MC54/74HC14A, Schmitt-trigger

inverter. The HC14A squares−up the input waveform and

feeds the HC4020A. Selecting outputs Q5, Q10, Q11, and

Q12 causes a reset every 3600 clocks. The HC20 decodes the

counter outputs, produces a single (narrow) output pulse,

and resets the binary counter. The resulting output frequency

is 1.0 pulse/minute.

VCC

VCC

120Vac

60Hz

1.0M

≥20pF

1/6 of HC14A

NOTE:

Ground MUST be isolated

by a transformer or

opto−isolator for safety

reasons.

HC4020A

13

Clock

Q5

12

Q10

10

Q11

9

Q12

1.0 Pulse/Minute

1

1/2

8 2 1/2 6

Output

HC20

4

5

HC20

Figure 9. Time−Base Generator

http://onsemi.com

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