SN74HC257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

These 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 (G\\) input is at a high logic level.

To ensure the high-impedance state during power up or power down, (G\\) 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

• Wide Operating Voltage Range of 2 V to 6 V
• High-Current Inverting Outputs Drive up to 15 LSTTL Loads
• Low Power Consumption, 80-µA Max ICC
• ’HC257 ...Typical tpd = 9 ns
• ’HC258 ...Typical tpd = 12 ns
• ±6-mA Output Drive at 5 V
• Low Input Current of 1 µA Max
• Provides Bus Interface from Multiple Sources in High-Performance Systems