SN54ABT574, SN74ABT574A

OCTAL EDGE-TRIGGERED D-TYPE FLIP-FLOPS

WITH 3-STATE OUTPUTS

SCBS191E – JANUARY 1991 – REVISED NOVEMBER 2002

2

POST OFFICE BOX 655303

description/ordering information (continued)

A buffered output-enable (OE) input can be used to place the eight outputs in either a normal logic state (high

or low logic levels) or the high-impedance state. In the high-impedance state, the outputs neither load nor drive

the bus lines significantly. The high-impedance state and increased drive provide the capability to drive bus

lines without need for interface or pullup components.

OE does not affect the internal operations of the flip-flops. Old data can be retained or new data can be entered

while the outputs are in the high-impedance state.

resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver.

preventing damaging current backflow through the device when it is powered down.

terminal assignments

1234

A

1D

OE

VCC

1Q

B

3D

3Q

2D

2Q

C

5D

4D

5Q

4Q

D

7D

7Q

6D

6Q

E

GND

8D

CLK

8Q

FUNCTION TABLE

(each flip-flop)

INPUTS

OUTPUT

OE

CLK

D

Q

L

↑

H

H

L

↑

LL

L

H or L

X

Q0

H

X

X

Z

logic diagram (positive logic)

OE

CLK

1D

1Q

To Seven Other Channels

C1

1

11

2

19

1D

Pin numbers shown are for the DB, DW, FK, J, N, NS, PW, RGY, and W packages.

SN74ABT574A . . . GQN PACKAGE

(TOP VIEW)

1

234

A

B

C

D

E