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.

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 A

• 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*

MC74HC138AD属于集成电路（IC） > 信号开关，多路复用器，解码器。安森美半导体公司制造生产的MC74HC138AD信号开关，多路复用器，解码器逻辑型信号开关、多路复用器和编码器 IC 可用于对以数字格式表示数据的电信号进行路由和选择。这些器件与设计用于模拟信号的类似产品有所不同，它们保留的信息表示为两个电状态之一，而不是两个外部界限内的无穷变化量。