TLF5207

January 1988

MM54HC299MM74HC299

8-Bit TRI-STATE

Universal Shift Register

General Description

This 8-bit TRI-STATE shiftstorage register utilizes advanced

silicon-gate CMOS technology Along with the low power

consumption and high noise immunity of standard CMOS

integrated circuits it has the ability to drive 15 LS-TTL

loads This circuit also features operating speeds compara-

ble to the equivalent low power Schottky device

The MM54HC299MM74HC299 features multiplexed in-

putsoutputs to achieve full 8-bit data handling in a single

20-pin package Due to the large output drive capability and

TRI-STATE feature this device is ideally suited for interfac-

ing with bus lines in a bus oriented system

Two function select inputs and two output control inputs are

used to choose the mode of operation as listed in the func-

tion table Synchronous parallel loading is accomplished by

taking both function select lines S0 and S1 high This places

the TRI-STATE outputs in a high impedance state which

permits data applied to the inputoutput lines to be clocked

into the register Reading out of the register can be done

while the outputs are enabled in any mode A direct overrid-

ing CLEAR input is provided to clear the register whether

the outputs are enabled or disabled

The 54HC74HC logic family is functionally as well as pinout

compatible with the standard 54LS74LS logic family All

inputs are protected from damage due to static discharge by

Features

Y

Typical operating frequency 40 MHz

Y

Typical propagation delay 20 ns

Y

Low quiescent current 80 mA maximum (74HC)

Y

High output drive for bus applications

Y

Low quiescent current 1 mA maximum

Connection Diagram

Dual-In-Line Package

TLF5207 1

Order Number MM54HC299 or MM74HC299

TRI STATE

is a registered trademark of National Semiconductor Corporation

C1995 National Semiconductor Corporation

RRD B30M105Printed in U S A