The CD74HCT257E is a quad 2-input multiplexer which selects 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.
Typical Propagation Delay (In to Output) = 12ns at VCC = 5V, CL = 15pF, TA = 25°C
Wide Operating Temperature Range: –55°C to 125°C
Balanced Propagation Delay and Transition Times
Significant Power Reduction Compared to LSTTL Logic ICs
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
16 pin DIP. Manufactured by Harris.