SN54ALS29821 . . . JT PACKAGE

SN74ALS29821 . . . DW OR NT PACKAGE

(TOP VIEW)

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24

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OE

1D

2D

3D

4D

5D

6D

7D

8D

9D

10D

GND

1Q

2Q

3Q

4Q

5Q

6Q

7Q

8Q

9Q

10Q

CLK

SN54ALS29821, SN74ALS29821

10-BIT BUS-INTERFACE FLIP-FLOPS

WITH 3-STATE OUTPUTS

SDAS145B – JANUARY 1986 – REVISED JANUARY 1995

Copyright

1

POST OFFICE BOX 655303

Wider Address/Data Paths or Buses With

Parity

Circuitry

dc Loading Effects

Small-Outline (DW) Packages and Standard

Plastic (NT) and Ceramic (JT) 300-mil DIPs

description

These 10-bit edge-triggered D-type flip-flops

feature 3-state outputs designed specifically for

driving highly capacitive or relatively low-impedance loads. These devices are particularly suitable for

implementing wider buffer registers, I/O ports, bidirectional bus drivers with parity, and working registers.

On the positive transition of the clock (CLK) input, the Q outputs are true to the data (D) input.

A buffered output-enable (OE) input can place the ten outputs in either a normal logic state (high or low logic

levels) or a high-impedance state. The outputs also are 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 bus lines without interface or pullup components.

OE 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 in the high-impedance state.

The SN54ALS29821 is characterized for operation over the full military temperature range of – 55

°C to 125°C.

The SN74ALS29821 is characterized for operation from 0

°C to 70°C.

FUNCTION TABLE

(each flip-flop)

INPUTS

OUTPUT

OE

CLK

D

Q

L

↑

H

H

L

↑

LL

L

LX

Q0

H

X

X

Z

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.