5-1

FACT DATA

Product Preview

9Bit Register With 3State

Outputs (NonInverting)

The MC74AC/ACT823 consists of nine D-type edge-triggered flip-flops. This

device has 3-state outputs for bus systems, organized in a broadside pinning. In

addition to the clock and output enabled pins, the buffered clock (CP) and buffered

Output Enable (OE) are common to all flip-flips. The flip-flops will store the state of

their individual D inputs that meet the setup and hold time requirements on the

LOW-to-HIGH CP transition. With OE LOW, the contents of the flip-flops are available

at the outputs. When OE is HIGH, the outputs go to the high impedance state.

Operation of the OE input does not affect the state of the flip-flops. The

MC74AC/ACT823 has Clear (CLR) and Clock Enable (EN) pins. These devices are

ideal for parity bus interfacing in high performance systems.

When CLR is LOW, and OE is LOW, the outputs are LOW. When CLR is HIGH,

data can be entered into the flip-flops. When EN is LOW, data on the inputs is

transferred to the outputs on the LOW-to-HIGH clock transition. When EN is HIGH,

the outputs do not change state, regardless of the data or clock input transitions.

• 3-State Outputs for Bus Interfacing

• Broad Side Pin Configuration

• ACT has TTL – Compatible Inputs

• High Speed Parallel Positive Edge-Triggered D-Type Flip-Flops

• High Performance Bus Interface Buffering for Busses Carrying Parity

• Outputs Source/Sink 24 mA

Pinout: 24-Lead Packages (Top View)

23

24

22

21

20

19

18

VCC

17

O0

O1

O2

O3

O4

O5

O6

2

1

3

4

5

6

7

8

OE1

D0

D1

D2

D3

D4

D5

D6

16

9

O7

D7

15

10

O8

D8

14

11

EN

CLR

13

12

CP

GND

FUNCTION TABLE

Inputs

Internal

Outputs

Operating Mode

OE

CLR

EN

CP

Dn

Q

O

Operating Mode

H

X

L

↑

L

L

Z

High Z

H

X

L

↑

H

H

Z

High Z

H

L

X

X

X

L

Z

Clear

L

L

X

X

X

L

L

Clear

H

H

H

X

X

NC

Z

Hold

L

H

H

X

X

NC

NC

Hold

H

H

L

↑

L

L

Z

Load

H

H

L

↑

H

H

Z

Load

L

H

L

↑

L

L

L

Load

L

H

L

↑

H

H

H

Load

H = HIGH Voltage Level; L = LOW Voltage Level; X = Immaterial; Z = High Impedance State;

↑ = LOW-to-High Transition; NC = No Change

This document contains information on a product under development. Motorola reserves the right to change or discontinue this product without notice.

MC74AC823

MC74ACT823

9-BIT REGISTER WITH

3-STATE OUTPUTS

N SUFFIX

CASE 724-03

PLASTIC PACKAGE

1

24

PIN NAMES

Data Inputs

Data Outputs

Output Enable

Clock Enable

Clear

Clock Input

D0 – D8

O0 – O8

OE

EN

CLR

CP

DW SUFFIX

CASE 751E-04

SOIC PACKAGE