1. General description

The 74AHC/AHCT157 are high-speed Si-gate CMOS devices and are pin compatible with Low

Power Schottky TTL (LSTTL). They are specified in compliance with JEDEC standard no. 7A.

The 74AHC/AHCT157 are quad 2-input multiplexer which select 4 bits of data from two sources

under the control of a common data select input (S). The enable input (E) is active LOW. When E is

HIGH, all of the outputs (1Y to 4Y) are forced LOW regardless of all other input conditions.

Moving the data from two groups of registers to four common output buses is a common use of

the 74AHC/AHCT157. The state of the common data select input (S) determines the particular

register from which the data comes. It can also be used as function generator. The device is useful

for implementing highly irregular logic by generating any four of the 16 different functions of two

variables with one variable common. The 74AHC/AHCT157 is logic implementation of a 4-pole,

2-position switch, where the position of the switch is determine by the logic levels applied to S.

The logic equations are:

• 1Y = E × (1I1 × S + 1I0 × S)

• 2Y = E × (2I1 × S + 2I0 × S)

• 3Y = E × (3I1 × S + 3I0 × S)

• 4Y = E × (4I1 × S + 4I0 × S)

2. Features

• Balanced propagation delays

• All inputs have a Schmitt-trigger action

• Inputs accepts voltages higher than VCC

• Multiple input enable for easy expansion

• Ideal for memory chip select decoding

• For 74AHC157 only: operates with CMOS input levels

• For 74AHCT157 only: operates with TTL input levels

• ESD protection:

• HBM JESD22-A114E exceeds 2000 V

• MM JESD22-A115-A exceeds 200 V

• CDM JESD22-C101C exceeds 1000 V

• Multiple package options

• Specified from -40 °C to +85 °C and from -40 °C to +125 °C

74AHC157属于集成电路（IC） > 信号开关，多路复用器，解码器。安世半导体(中国)有限公司制造生产的74AHC157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。