DM74LS374 datasheet(2/8 Pages) NSC

2 / 8 page

General Description (Continued)

The eight latches of the DM5474LS373 are transparent D-

type latches meaning that while the enable (G) is high the Q

outputs will follow the data (D) inputs When the enable is

taken low the output will be latched at the level of the data

that was set up

The eight flip-flops of the DM5474LS374 are edge-trig-

gered D-type flip flops On the positive transition of the

clock the Q outputs will be set to the logic states that were

set up at the D inputs

A buffered output control input can be used to place the

eight outputs in either a normal logic state (high or low logic

levels) or a high-impedance state In the high-impedance

state the outputs neither load nor drive the bus lines signifi-

cantly

The output control does not affect the internal operation of

the latches or flip-flops That is the old data can be retained

or new data can be entered even while the outputs are off

Function Tables

DM5474LS373

Output

Enable

Output

Control

DM5474LS374

Output

Clock

Output

Control

H e High Level (Steady State) L e Low Level (Steady State) X e Don’t Care

u e Transition from low-to-high level Z e High Impedance State

Q0 e The level of the output before steady-state input conditions were established

Logic Diagrams

DM5474LS373

Transparent Latches

TLF6431 – 3

DM5474LS374

Positive-Edge-Triggered Flip-Flops

TLF6431 – 4

DM74LS374 Scheda tecnica(PDF) 2 Page - National Semiconductor (TI)