SN54F573, SN74F573

OCTAL TRANSPARENT D-TYPE LATCHES

WITH 3-STATE OUTPUTS

SDFS011A – MARCH 1987 – REVISED OCTOBER 1993

Copyright

2–1

POST OFFICE BOX 655303

Small-Outline Packages, Ceramic Chip

Carriers, and Standard Plastic and Ceramic

300-mil DIPs

description

These 8-bit latches feature 3-state outputs

designed specifically for driving highly capacitive

or relatively low-impedance loads. They are

particularly suitable for implementing buffer

registers, I/O ports, bidirectional bus drivers, and

working registers.

The eight latches of the

′F573 are transparent

D-type latches. While the latch enable (LE) input

is high, the Q outputs follow the data (D) inputs.

When the latch enable is taken low, the Q outputs

are latched at the logic levels set up at the D

inputs.

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 a 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.

The output enable (OE) input does not affect the internal operations of the latches. Old data can be retained

or new data can be entered while the outputs are in the high-impedance state.

The SN54F573 is characterized for operation over the full military temperature range of – 55

°C to 125°C. The

SN74F573 is characterized for operation from 0

°C to 70°C.

FUNCTION TABLE

(each latch)

INPUTS

OUTPUT

OE

LE

D

Q

L

H

H

H

L

HL

L

L

LX

Q0

H

X

X

Z

1

2

3

4

5

6

7

8

9

10

20

19

18

17

16

15

14

13

12

11

OE

1D

2D

3D

4D

5D

6D

7D

8D

GND

1Q

2Q

3Q

4Q

5Q

6Q

7Q

8Q

LE

SN54F573 ...J PACKAGE

SN74F573 . . . DW OR N PACKAGE

(TOP VIEW)

3

2

1 20 19

910 11 12 13

4

5

6

7

8

18

17

16

15

14

2Q

3Q

4Q

5Q

6Q

3D

4D

5D

6D

7D

SN54F573 . . . FK PACKAGE

(TOP VIEW)

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of Texas Instruments

standard warranty. Production processing does not necessarily include

testing of all parameters.