The MC74HC257N 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 MC74HC257N 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 mA
High Noise Immunity Characteristic of CMOS Devices
16 pin DIP. Manufactured by Motorola.