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2

Unit Loading/Fan Out

Functional Description

The 74F574 consists of eight edge-triggered flip-flops with

individual D-type inputs and 3-STATE true 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. Opera-

tion of the OE input does not affect the state of the flip-

flops.

Function Table

H

= HIGH Voltage Level

L

= LOW Voltage Level

X

= Immaterial

Z

= High Impedance

 = LOW-to-HIGH Transition

NC

= No Change

Logic Diagram

Please note that this diagram is provided only for the understanding of logic operations and should not be used to estimate propagation delays.

Pin Names

Description

U.L.

HIGH/LOW

Data Inputs

1.0/1.0

20

µA/−0.6 mA

CP

Clock Pulse Input (Active LOW)

1.0/1.0

20

µA/−0.6 mA

OE

3-STATE Output Enable Input (Active LOW)

1.0/1.0

20

µA/−0.6 mA

3-STATE Outputs

150/40 (33.3)

−3 mA/24 mA (20 mA)

Inputs

Internal Outputs

Function

OE

CP

D

Q

O

H

H

L

NC

Z

Hold

HHH

NC

Z

Hold

H



LL

Z

Load

H



HH

Z

Load

L



L

L

L

Data Available

L



H

H

H

Data Available

L

H

L

NC

NC

No Change in Data

L

H

H

NC

NC

No Change in Data