SN74AS1843

9BIT BUS INTERFACE DTYPE LATCHES WITH 3STATE OUTPUTS

SDAS127 − APRIL 1987

POST OFFICE BOX 655303

1

Copyright

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.

Provides Minimum Lead Inductance in High

Current Switching Applications

Bus-Lines Directly

Necessary for Wider Address/Data Paths or

Buses With Parity

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description

This 9-bit latch device features three-state outputs

designed specifically for driving highly capacitive

or relatively low-impedance loads. It is particularly

suitable for implementing buffer registers, I/O

ports, bidirectional bus drivers, and working

registers.

The nine latches are transparent D-type and have

noninverting data (D) inputs.

A buffered output control (OC) input can be used

to place the nine outputs in either a normal logic

state (high or low 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 the bus lines in a

bus-organized system without need for interface

or pullup components.

The output control (OC) does not affect the

internal operation of the flip-flops. Old data can be

retained or new data can be entered while the

outputs are off.

The SN74AS1843 is characterized for operation

from 0

°C to 70°C.

NT Package

(Top View)

1

2

3

4

5

6

7

8

9

10

11

12

24

23

22

21

20

19

18

17

16

15

14

13

5Q

4Q

3Q

2Q

1Q

VCC

OC

1D

2D

3D

4D

5D

6Q

7Q

8Q

9Q

PRE

C

GND

CLR

9D

8D

7D

6D

PRE

CLR

OC

CD

Q

LX

L

X

X

H

HL

L

X

X

L

HH

L

H

L

L

HH

L

H

H

H

HH

L

L

X

QO

XX

H

X

X

Z

INPUTS

OUTPUT

FUNCTION TABLE

†

This symbol is in accordance with ANSI/IEEE Std 91-1984

and IEC Publication 617-12,

7

20

17

19

8

9

10

11

12

13

14

15

5

4

3

2

1

24

23

22

EN

1Q

2Q

3Q

4Q

5Q

6Q

7Q

8Q

1D

C1

R

S2

OC

PRE

CLR

C

1D

2D

3D

4D

5D

6D

7D

8D

16

21

9Q

9D

2