CD74HC257

具有同向三态输出的高速 CMOS 逻辑四路 2 输入多路复用器

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.

.

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