SN74HCT257数据手册集成电路（IC）的信号开关多路复用器解码器规格书PDF

描述 Description

The ’HCT257 devices are designed to multiplex signals from 4-bit data sources to 4-output data lines in bus-organized systems. The 3-state outputs do not load the data lines when the output-enable (OE)\\ input is at the high logic level.

To ensure the high-impedance state during power up or power down, OE\\ should be tied to VCC through a pullup resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver.

特性 Features

• Operating Voltage Range of 4.5 V to 5.5 V
• High-Current 3-State Outputs Interface Directly With System Bus
• Typical tpd = 17 ns
• Low Power Consumption, 80-µA Max ICC
• ±6-mA Output Drive at 5 V
• Low Input Current of 1 µA Max
• Inputs Are TTL-Voltage Compatible
• Provide Bus Interface From Multiple Sources in High-Performance Systems
• Buffered Inputs and Outputs