MM54HC257/MM74HC257Quad 2-Channel TRI-STATEÉ MultiplexerGeneral Des criptionThis QUAD 2-TO-1 line data selector/multiplexer utilizes advancedsilicon-gate CMOS technology. Along with the highnoise immunity and low power dissipation of standardCMOS integrated circuits, it possesses the ability to drive upto 15 LS-TTL loads. The large output drive capability coupledwith the TRI-STATE feature make this device ideal forinterfacing with bus lines in a bus organized system. Whenthe OUTPUT CONTROL input line is taken high, the outputsof all four multiplexers are sent into a high impedance state.When the OUTPUT CONTROL line is low, the SELECT inputchooses whether the A or B input is used.The 54HC/74HC logic family is speed, function, and pin-outcompatible with the standard 54LS/74LS logic family. Allinputs are protected from damage due to static discharge byinternal diode clamps to VCC and ground.FeaturesY Typical propagation delay: 12 nsY Wide power supply range: 2V±6VY Low quiescent current: 80 mA maximum (74HC Series)Y TRI-STATE outputs for connection to system buses.