74ACT257集成电路（IC）的信号开关多路复用器解码器规格书PDF中文资料

74ACT257属于集成电路（IC）的信号开关多路复用器解码器。由意法半导体集团制造生产的74ACT257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。

DESCRIPTION

The 74ACT257 is an advanced high-speed CMOS QUAD 2-CHANNEL MULTIPLEXER (3-STATE) fabricated with sub-micron silicon gate and double-layer metal wiring C2MOS tecnology. It is composed of an independent 2-channel multiplexer with common SELECT and ENABLE (OE)inputs. It is a non-inverting multiplexer. When the ENABLE input is held HIGH, the outputs are forced to a high impedance state. When the SELECT input is held LOW, A data is selected; when SELECT input is held HIGH, B data is selected.

■ HIGH SPEED: tPD = 5 ns (TYP.) at VCC = 5V

■ LOW POWER DISSIPATION: ICC = 4 µA(MAX.) at TA=25°C

■ COMPATIBLE WITH TTL OUTPUTS VIH = 2V (MIN.), VIL = 0.8V (MAX.)

■ 50Ω TRANSMISSION LINE DRIVING CAPABILITY

■ SYMMETRICAL OUTPUT IMPEDANCE: |IOH| = IOL = 24mA (MIN)

■ BALANCED PROPAGATION DELAYS: tPLH ≅ tPHL

■ OPERATING VOLTAGE RANGE: VCC (OPR) = 4.5V to 5.5V

■ PIN AND FUNCTION COMPATIBLE WITH 74 SERIES 257

■ IMPROVED LATCH-UP IMMUNITY