Quad 2-Input Data Selector/Multiplexer with 3-State Outputs
High–Performance Silicon–Gate CMOS

The MC74HC257 is identical in pinout to the LS257. The device inputs are compatible with standard CMOS outputs; with pullup resistors, they are compatible with LSTTL outputs.
This device selects a (4–bit) nibble from either the A or B inputs as determined by the Select input. The nibble is presented at the outputs in noninverted form when the Output Enable pin is at a low level. A high level on the Output Enable pin switches the outputs into the high–impedance state.
The HC257 is similar in function to the HC157 which do not have 3–state outputs.

• Output Drive Capability: 15 LSTTL Loads
• Outputs Directly Interface to CMOS, NMOS, and TTL
• Operating Voltage Range: 2 to 6 V
• Low Input Current: 1 µA
• High Noise Immunity Characteristic of CMOS Devices
• In Compliance with the Requirements Defined by JEDEC Standard No. 7A
• Chip Complexity: 108 FETs or 27 Equivalent Gates