SN74LS299 Universal shift / storage registers |

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Universal shift / storage registers

Universal shift / storage registers - SN74LS299


These Schottky TTL eight-bit universal registers feature multiplexed inputs/outputs to achieve full eight-bit data handling in a single 20-pin package. Two function-select inputs and two output-control inputs can be used to choose the modes of operation listed in the function table.

Synchronous parallel loading is accomplished by taking both function-select lines, S0 and S1, high. This places the three-state outputs in a high-impedance state, which permits data that is applied on the input/output lines to be clocked into the register. Reading out of the register can be accomplished while the outputs are enabled in any mode. A direct overriding input is provided to clear the register whether the outputs are enabled or off.



  • Multiplexed Inputs/Outputs Provide Improved Bit Density
  • Four Modes of Operations:
    • Hold (Store)
    • Shift Left
    • Shift Right
    • Load Data
  • Operates with Outputs Enabled or at High Z
  • 3-State Outputs Drive Bus Lines Directly
  • Can Be Cascaded for N-Bit Word Lengths
  • SN54LS323 and SN74LS323 Are Similar But Have Synchronous Clear
  • Applications:
    • Stacked or Push-Down Registers Buffer Storage, and Accumulator Registers



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Part number Order Technology Family VCC (Min) (V) VCC (Max) (V) Voltage (Nom) (V) F @ nom voltage (Max) (MHz) ICC @ nom voltage (Max) (mA) tpd @ nom Voltage (Max) (ns) IOL (Max) (mA) IOH (Max) (mA) 3-state output Rating Operating temperature range (C)
SN74LS299 Order now LS     4.75     5.25     5     35     53     39     24     -2.6     Yes     Catalog     0 to 70    
SN54LS299 Samples not available LS     4.75     5.25     5     35     53     39     24     -2.6     Yes     Military     -55 to 125