SDLS085 - DECEMBER 1972 - REVISED MARCH 1988
PRODUCTION DATA documents contain information current as of publicationdate. Products conform to specifications per the terms of Texas Instrumentsstandard warranty. Production processing does not necessarily include testingof all parameters.
These monolithic data selectors/multiplexers contain full on-chip binarydecoding to select one-of-eight data sources and feature a strobe-controlledthree-state output. The strobe must be at a low logic level to enable thesedevices. The three-state outputs permit a number of outputs to be connectedto a common bus. When the strobe input is high, both outputs are in a high-impedancestate in which both the upper and lower transistors of each totem-pole outputare off, and the output neither drives nor loads the bus significantly. Whenthe strobe is low, the outputs are activated and operate as standard TTL totem-poleoutputs.
To minimize the possibility that two outputs will attempt to take a commonbus to opposite logic levels, the output control circuitry is designed sothat the average output disable time is shorter than the average output enabletime. The SN54251 and SN74251 have output clamp diodes to attenuate reflectionson the bus line.
View more information about generic part numbers:SN54251, SN54LS251, SN54S251, SN74251, SN74LS251, SN74S251
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