SDAS217A - DECEMBER 1982 - REVISED DECEMBER 1994
These 8-bit addressable latches are designed for general-purposestorage applications in digital systems. Specific uses includeworking registers, serial-holding registers, and active-high decodersor demultiplexers. They are multifunctional devices capable ofstoring single-line data in eight addressable latches and being a1-of-8 decoder or demultiplexer with active-high outputs.
Four distinct modes of operation are selectable by controlling theclear (
) and enable(G\) inputs as shown in the function table. In the addressable-latchmode, data at the data-in terminal is written into the addressedlatch. The
addressed latch follows the data input with all unaddressedlatches remaining in their previous states. In the memory mode, alllatches remain in their previous states and are unaffected by thedata or address inputs. To eliminate the possibility of enteringerroneous data in the latches, G\ should be held high (inactive)while the address lines are changing. In the 1-of-8 decoding ordemultiplexing mode, the addressed output follows the level of the Dinput with all other outputs low. In the clear mode, all outputs arelow and unaffected by the address and data inputs.
The SN54ALS259 is characterized for operation over the fullmilitary temperature range of -55°C to 125°C. TheSN74ALS259 is characterized for operation from 0°C to 70°C.
View more information about generic part numbers:SN54ALS259, SN74ALS259
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