DM74LS259

These DM74LS259 8-bit addressable latches are designed for general purpose storage applications in digital systems. Specific uses include working registers, serial-holding registers,and active-high decoders or demultiplexers. DM74LS259 are mul-tifunctional devices capable of storing single-line data in eight addressable latches, and being a 1-of-8 decoder or demultiplexer with active-high outputs.

Four distinct modes of operation are selectable by control-ling the clear and enable inputs as enumerated in the func-tion table. In the addressable-latch mode, data at the data-in terminal is written into the addressed latch. The DM74LS259 addressed latch will follow the data input with all unad-dressed latches remaining in their previous states. In the memory mode, all latches remain in their previous states and are unaffected by the data or address inputs. To elimi-nate the possibility of entering erroneous data in the latches, the enable should be held HIGH (inactive) while the address lines are changing. In the 1-of-8 decoding or demultiplexing mode, the addressed output will follow the level of the D input with all other outputs LOW. In the clear mode, all outputs are LOW and unaffected by the address and data inputs.