HCF4021 Datasheet, PDF(4/13 Page) STMicroelectronics – Asynchronous parallel input or synchronous serial-in/serial-out 8-stage static shift register

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HCF4021 Datasheet, PDF (4/13 Pages) STMicroelectronics – Asynchronous parallel input or synchronous serial-in/serial-out 8-stage static shift register

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Functional description

2

Functional description

HCF4021

Figure 2. Logic diagram

3

3

3

3

3

3

3

3

6HULDOLQSXW

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' 34

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3DUDOOHOVHULDOFRQWURO

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3

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36

S

Q

&/

S

S

Q

Q

&/

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' 34

' 34

&/ 36

&/ 36

&/ 36

3

'4

&/ 36

3

'4

&/ 36

&/

&/

&/

S

Q

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S

Q

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4

4

4

4

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S

Q

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*$06&%

Clock

X(1)

X(1)

X(1)

X(1)

1. Donât care

Serial

input

X(1)

X(1)

X(1)

X(1)

0

1

X(1)

Table 3. Truth table

Parallel/serial

control

PI-1

PI-n

1

0

0

1

0

1

1

1

0

1

1

1

0

X(1)

X(1)

0

X(1)

X(1)

X(1)

X(1)

X(1)

Q1 (internal)

0

0

1

1

0

1

Q1

Qn

0

1

0

1

Qn-1

Qn-1

Qn

Figure 3. Input equivalent circuit

9''

,1387

966

*$06&%

4/13

DocID008216 Rev 3

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