General description

The 74HC257; 74HCT257 are high-speed Si-gate CMOS devices and are pin compatible with Low-power Schottky TTL (LSTTL).

The 74HC257 and 74HCT257 have four identical 2-input multiplexers with 3-state outputs, which select 4 bits of data from two sources and are controlled by a common data select input (S).

The data inputs from source 0 (1I0 to 4I0) are selected when input S is LOW and the data inputs from source 1 (1I1 to 4I1) are selected when S is HIGH. Data appears at the outputs (1Y to 4Y) in true (non-inverting) form from the selected inputs.

The 74HC257 and 74HCT257 are the logic implementation of a 4-pole, 2-position switch, where the position of the switch is determined by the logic levels applied to S. The outputs are forced to a high-impedance OFF-state when OE is HIGH.

Features

■ Non-inverting data path

■ 3-state outputs interface directly with system bus

■ Complies with JEDEC standard no. 7A

■ ESD protection:

♦ HBM JESD22-A114E exceeds 2000 V

♦ MM JESD22-A115-A exceeds 200 V

■ Multiple package options

■ Specified from −40 °C to +85 °C and from −40 °C to +125 °C

74HCT257N属于集成电路（IC） > 信号开关，多路复用器，解码器。恩智浦半导体公司制造生产的74HCT257N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。