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

The MC54/74HC251 is identical in pinout to the LS251. The device inputs are compatible with standard CMOS outputs; with pullup resistors, they are compatible with LSTTL outputs.
This device selects one of the eight binary Data Inputs, as determined by the Address Inputs. The Output Enable pin must be a low level for the selected data to appear at the outputs. If Output Enable is high, both the Y and the Y outputs are in the high–impedance state. This 3–state feature allows the HC251 to be used in bus–oriented systems.
The HC251 is similar in function to the HC151 which does not have 3–state outputs.

• Output Drive Capability: 10 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: 134 FETs or 33.5 Equivalent Gates