SN74LS399N

Overview

The SN74LS399N is a high-speed CMOS logic component manufactured by Texas Instruments, belonging to the LS (Low-power Schottky) series. It functions as a 16-bit universal shift register with parallel load capability. The device features a serial input and serial output, along with 16 parallel data inputs and outputs. It operates within a standard voltage range typical for LS logic families and supports bidirectional shifting. The package type is PDIP-20, suitable for through-hole mounting on printed circuit boards.

Feature Summary

• Supports 16-bit serial-in/serial-out and serial-in/parallel-out operations
• Enables parallel loading of data into all flip-flops simultaneously
• Provides bidirectional shifting capability under control signals
• Includes asynchronous clear function to reset all stages

Applications

• Data storage in digital systems requiring temporary holding of binary information
• Serial-to-parallel conversion for interfacing serial communication protocols
• Parallel-to-serial conversion for transmitting data over single lines
• Implementation of delay lines or tapped delay networks in signal processing

Procurement Notes

Verify the exact part number SN74LS399N against manufacturer datasheets to confirm pinout compatibility and electrical specifications. Ensure the supplier provides genuine Texas Instruments components with traceable lot codes. Check for RoHS compliance if required by your assembly standards. Confirm packaging details match the PDIP-20 specification. Validate operating temperature ranges align with your system requirements before finalizing procurement.

Selection Notes

Select this component when a 16-bit shift register with parallel load is needed in LS logic environments. Consider power consumption differences compared to HC or HCT families. Evaluate speed requirements as LS devices have moderate propagation delays. Ensure voltage levels are compatible with existing system logic thresholds. Verify package availability and lead times for production planning purposes.

Part Context

The SN74LS399N is part of Texas Instruments' extensive line of discrete logic ICs designed for general-purpose digital applications. It complements other shift registers like the SN74LS166 or SN74LS194 but offers specific 16-bit width. This family remains relevant in legacy systems and educational contexts where LS logic characteristics are preferred or required for compatibility with older designs.

Replacement Considerations

Direct replacements may include SN74LS166 or SN74LS194 depending on functional needs, though pinouts differ. Cross-reference with SN54LS399 for military temperature range variants. Verify logical equivalence rather than physical interchangeability. Consult official substitution guides from Texas Instruments for validated alternatives.