CD74HCT257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 ’HC257 and ’HCT257 are quad 2-input multiplexers which select four bits of data from two sources under the control of a common Select Input (S). The Output Enable input (OE\\) is active LOW. When OE\\ is HIGH, all of the outputs (1Y-4Y) are in the high impedance state regardless of all other input conditions.
Moving data from two groups of registers to four common output buses is a common use of the 257. The state of the Select input determines the particular register from which the data comes. It can also be used as a function generator.

特性 Features

• Buffered Inputs
• Typical Propagation Delay (In to Output) = 12ns at VCC = 5V, CL = 15pF, TA = 25°C
• Fanout (Over Temperature Range)
- Standard Outputs...10 LSTTL Loads
• Bus Driver Outputs...15 LSTTL Loads
• Wide Operating Temperature Range...–55°C to 125°C
• Balanced Propagation Delay and Transition Times
• Significant Power Reduction Compared to LSTTL Logic ICs
• HC Types
- 2V to 6V Operation
• High Noise Immunity: NIL = 30%, NIH = 30% of VCC at VCC = 5V
• HCT Types
- 4.5V to 5.5V Operation
• Direct LSTTL Input Logic Compatibility, VIL = 0.8V (Max), VIH = 2V (Min)
• CMOS Input Compatibility, Il 1µA at VOL, VOH
Data sheet acquired from Harris Semiconductor