General Description
The MM74HC251 8-channel digital multiplexer with 3-STATE outputs utilizes advanced silicon-gate CMOS technology. Along with the high noise immunity and low power consumption of standard CMOS integrated circuits, it possesses the ability to drive 10 LS-TTL loads. The large output drive capability and 3-STATE feature make this part ideally suited for interfacing with bus lines in a bus oriented system.
This multiplexer features both true (Y) and complement (W) outputs as well as a STROBE input. The STROBE must be at a low logic level to enable this device. When the STROBE input is HIGH, both outputs are in the high impedance state. When enabled, address information on the data select inputs determines which data input is routed to the Y and W outputs. The 74HC logic family is speed, function, as well as pinout compatible with the standard 74LS logic family. All inputs are protected from damage due to static discharge by internal diode clamps to VCC and ground.

FEATUREs
■ Typical propagation delay Data select to Y: 26 ns
■ Wide supply range: 2–6V
■ Low power supply quiescent current: 80 µA maximum (74HC)
■ 3-STATE outputs for interface to bus oriented systems