SN74LS684N

Overview

The SN74LS684N is an 8-bit magnitude comparator manufactured by onsemi, belonging to the LS (Low-Power Schottky) series. It compares two eight-bit binary or BCD words and provides active-low outputs for identity (A=B) and greater-than (A>B) conditions. The device utilizes a 20-pin PDIP package and features totem pole outputs. Designed for TTL compatibility, it supports standard digital logic applications requiring precise numerical comparison between parallel data inputs.

Feature Summary

• Performs 8-bit magnitude comparisons between binary or BCD words
• Provides active-low outputs for equality and greater-than conditions
• Utilizes Low-Power Schottky technology for enhanced speed and power efficiency
• Features totem pole outputs for direct interfacing with TTL circuits

Applications

• Digital arithmetic logic units
• Address decoding systems
• Error detection circuits
• Control logic for numerical displays

Procurement Notes

Verify the manufacturer marking matches onsemi specifications when sourcing from third-party distributors. Confirm the package type is 20-pin PDIP and check for any suffix variations that may indicate temperature range or tape-and-reel options. Ensure the component is in active production status as listed in official catalogs before finalizing procurement orders.

Selection Notes

Select this component when an 8-bit comparison function is required within a TTL-compatible system. The LS series offers a balance of switching speed and power consumption suitable for general-purpose digital designs. Consider the active-low output polarity when designing interface logic to ensure correct signal interpretation by downstream components.

Part Context

This part belongs to the SN74LS6xx family of comparators, which includes variants like the SN74LS682 and SN74LS688. These devices share similar architectural principles but differ in output configurations. The SN74LS684N specifically focuses on providing both identity and greater-than signals, distinguishing it from identity-only or less-than focused counterparts in the same logical family.

Replacement Considerations

Compatible substitutes include the SN74LS684N from Texas Instruments and other manufacturers producing equivalent LS-series 8-bit comparators. Verify pinout compatibility and electrical characteristics such as propagation delay and supply current before substitution.