74LS257APCQM

更新时间： 2024-02-20 08:23:00

品牌	Logo	应用领域
飞兆/仙童 - FAIRCHILD		复用器
页数	文件大小	规格书
5页	59K
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数据手册

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74LS257APCQM 数据手册

June 1989

Revised November 1999

DM74LS257B

3-STATE Quad 2-Data Selectors/Multiplexers

for data buses. It also permits the use of standard TTL reg-

isters for data retention throughout the system.

General Description

These Schottky-clamped high-performance multiplexers

feature 3-STATE outputs that can interface directly with

data lines of bus-organized systems. With all but one of the

common outputs disabled (at a high impedance state), the

low impedance of the single enabled output will drive the

bus line to a HIGH or LOW logic level. To minimize the pos-

sibility that two outputs will attempt to take a common bus

to opposite logic levels, the output enable circuitry is

designed such that the output disable times are shorter

than the output enable times.

Features

■ 3-STATE versions LS157 and LS158 with same pinouts

■ Schottky-clamped for significant improvement in A-C

performance

■ Provides bus interface from multiple sources in

high-performance systems

■ Average propagation delay from data input 12 ns

■ Typical power dissipation: 50 mW

This 3-STATE output feature means that n-bit (paralleled)

data selectors with up to 258 sources can be implemented

Ordering Code:

Order Number Package Number

Package Description

DM74LS257BM

DM74LS257BN

M16A

N16E

16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow

16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide

Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.

Connection Diagram

Logic Diagram

Function Table

Inputs

Output

Output Y

LS257

Select

Control

H = HIGH Level

L = LOW Level

X = Don’t Care

Z = High Impedance (off)

DS006417

www.fairchildsemi.com

12 3 4 5

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与74LS257APCQM相关器件

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74LS257APCQR	FAIRCHILD	获取价格	暂无描述
74LS257ASC	FAIRCHILD	获取价格	Multiplexer, 4-Func, 2 Line Input, TTL, PDSO16
74LS257B	NXP	获取价格	LS SERIES, QUAD 2 LINE TO 1 LINE MULTIPLEXER, TRUE OUTPUT, PDIP16
74LS257DC	FAIRCHILD	获取价格	Multiplexer, 4-Func, 2 Line Input, TTL, CDIP16,
74LS257DCQM	FAIRCHILD	获取价格	Multiplexer, 4-Func, 2 Line Input, TTL, CDIP16,
74LS257FCQR	FAIRCHILD	获取价格	Multiplexer, 4-Func, 2 Line Input, TTL, CDFP16,
74LS257PCQM	FAIRCHILD	获取价格	Multiplexer, 4-Func, 2 Line Input, TTL, PDIP16,
74LS257PCQR	FAIRCHILD	获取价格	Multiplexer, 4-Func, 2 Line Input, TTL, PDIP16,
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74LS258AFC	FAIRCHILD	获取价格	Multiplexer, 4-Func, 2 Line Input, TTL, CDFP16,