SN54ALS29843, SN74ALS29843, SN74ALS29844

9BIT BUS INTERFACE DTYPE LATCHES WITH 3STATE OUTPUTS

SDAS151A − D2910 — JUNE 1988 — REVISED JANUARY 1990

POST OFFICE BOX 655303

Copyright

1

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.

Lines Directly

Necessary For Wider Address/Data Paths

or Buses With Parity

Loading

Outline” Packages and Standard Plastic

and Ceramic 300-Mil DIPs

description

These 9-bit latches feature three-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 nine latches are transparent D-type. The

′ALS29843 has noninverting data (D) inputs. The

′ALS29844 has inverting 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. The outputs are also in the high-impedance

state

during

power-up

and

power-down

conditions.

The

outputs

remain

in

the

high-impedance

state

while

the

device

is

powered-down. 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 latches. Old data can be retained or new

data can be entered while the outputs are off.

The SN54ALS29843 is characterized for operation over the full military range of − 55

°C to 125°C. The

SN74ALS29843 and SN74ALS29844 are characterized for operation from 0

°C to 70°C.

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OC

1D

2D

3D

4D

5D

6D

7D

8D

9D

CLR

GND

1Q

2Q

3Q

4Q

5Q

6Q

7Q

8Q

9Q

PRE

C

SN54ALS29843 . . . JT Package

SN74ALS29843 . . . DW or NT Package

(Top View)

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OC

1D

2D

3D

4D

5D

6D

7D

8D

9D

CLR

GND

1Q

2Q

3Q

4Q

5Q

6Q

7Q

8Q

9Q

PRE

C

SN74ALS29844 . . . DW or NT Package

(Top View)