描述 Description

The MC74HC138A is identical in pinout to the LS138. The device inputs are compatible with standard CMOS outputs; with pullup resistors, they are compatible with LSTTL outputs. The HC138A decodes a three bit Address to one of eight active low outputs. This device features three Chip Select inputs, two active low and one active high to facilitate the demultiplexing, cascading, and chip selecting functions. The demultiplexing function is accomplished by using the Address inputs to select the desired device output; one of the Chip Selects is used as a data input while the other Chip Selects are held in their active states.

特性 Features

? Output Drive Capability: 10 LSTTL Loads
? Outputs Directly Interface to CMOS, NMOS and TTL
? Operating Voltage Range: 2.0 to 6.0 V
? Low Input Current: 1.0 mA
? High Noise Immunity Characteristic of CMOS Devices
? In Compliance with the Requirements Defined by JEDEC Standard No. 7A
? Chip Complexity: 100 FETs or 29 Equivalent Gates
? Pb-Free Packages are Available*

簡介

MC74HC138A屬于集成電路（IC）的信號(hào)開關(guān)多路復(fù)用器解碼器。由制造生產(chǎn)的MC74HC138A信號(hào)開關(guān)，多路復(fù)用器，解碼器邏輯型信號(hào)開關(guān)、多路復(fù)用器和編碼器 IC 可用于對(duì)以數(shù)字格式表示數(shù)據(jù)的電信號(hào)進(jìn)行路由和選擇。這些器件與設(shè)計(jì)用于模擬信號(hào)的類似產(chǎn)品有所不同，它們保留的信息表示為兩個(gè)電狀態(tài)之一，而不是兩個(gè)外部界限內(nèi)的無窮變化量。