MC74AC564 MC74ACT564

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2

FUNCTIONAL DESCRIPTION

The MC74AC564/74ACT564 consists of eight edge-

triggered flip-flops with individual D-type inputs and

3-state complementary outputs. The buffered clock and

buffered Output Enable are common to all flip-flops. The

eight flip-flops will store the state of their individual D

inputs that meet the setup and hold times requirements on

the LOW-to-HIGH Clock (CP) transition. With the Output

Enable (OE) LOW, the contents of the eight flip-flops are

available at the outputs. When OE is HIGH, the outputs go

to the high impedance state. Operation of the OE input does

not affect the state of the flip-flops.

FUNCTION TABLE

Inputs

Internal Outputs

Function

OE

CP

D

Q

O

H

H

L

NC

Z

Hold

H

HH

NC

Z

Hold

H

LH

Z

Load

H

HL

Z

Load

L

LH

H

Data Available

L

HL

L

Data Available

L

HL

NC

NC

No Change in Data

L

H

H

NC

NC

No Change in Data

H = HIGH Voltage Level

L = LOW Voltage Level

X = Immaterial

Z = High Impedance

= LOW-to-HIGH Transition

NC = No Change

Figure 3. Logic Diagram

CD

Q

OE

CP

CD

Q

CD

Q

CD

Q

CD

Q

CD

Q

CD

Q

CD

Q

Please note that this diagram is provided only for the understanding of logic

operations and should not be used to estimate propagation delays.