54LS157/DM54LS157/DM74LS157,54LS158/DM54LS158/DM74LS158Quad 2-Line to 1-Line Data Selectors/MultiplexersGeneral Des criptionThese data selectors/multiplexers contain inverters anddrivers to supply full on-chip data selection to the four outputgates. A separate strobe input is provided. A 4-bit wordis selected from one of two sources and is routed to the fouroutputs. The LS157 presents true data whereas the LS158presents inverted data to minimize propagation delay time.ApplicationsY Expand any data input pointY Multiplex dual data busesY Generate four functions of two variables (one variableis common)Y Source programmable countersFeaturesY Buffered inputs and outputsY Typical Propagation TimeLS157 9 nsLS158 7 nsY Typical Power DissipationLS157 49 mWLS158 24 mWY Alternate Military/Aerospace device (54LS157,54LS158) is available. Contact a National SemiconductorSales Office/Distributor for specifications.