6 Detailed Description

6.1 Overview

The CD54/74AC574 and the CD54/74ACT574 octal D-type, 3-state, positive-edge-triggered flip-flops use the

RCA ADVANCED CMOS technology. The eight flip-flops enter data into their registers on the LOW-to-HIGH

transition of the clock (CP). The Output Enable (OE) controls the 3-state outputs and is independent of the

register operation. When the Output Enable (OE) is HIGH, the outputs are in the high-impedance state. The

CD54/74AC/ACT574 share the same pin configurations, and the CD54/74AC/ACT574 has non-inverted outputs.

The CD74AC/ACT574 are supplied in 20-lead dual-in-line plastic packages (E suffix) and in 20-lead dual-in-line

small-outline plastic packages (M suffix). Both package types are operable over the following temperature

ranges: Commercial (0 to 70°C); Industrial (-40 to +85°C); and Extended Industrial/Military (-55 to +125°C).

The CD54AC/ACT574, available in chip form (H suffix), are operable over the -55 to +125°C temperature range.

6.2 Functional Block Diagram

6.3 Device Functional Modes

Table 6-1. Truth Table

Output Enable

Latch Enable

Data

AC/ACT373

Output

L

H

H

H

L

H

L

L

L

L

I

L

L

L

h

H

H

X

X

Z

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CD54AC574, CD74AC574, CD54ACT574, CD74ACT574

SCHS292A – DECEMBER 1998 – REVISED MAY 2024

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