DM74LS85N

Comparators Overview

The DM74LS85N is a 4-bit magnitude comparator manufactured by onsemi, belonging to the 74LS logic series. It compares two 4-bit binary words and provides outputs indicating whether one word is greater than, less than, or equal to the other. The device utilizes Low-power Schottky (LS) TTL technology to achieve moderate speed with reduced power consumption compared to standard TTL. It features active-high outputs for the three comparison conditions: A>B, A<B, and A=B. The component is housed in a 16-pin Plastic Dual In-line Package (PDIP-16), suitable for through-hole mounting on printed circuit boards.

Comparators Feature Summary

• Performs parallel magnitude comparison of two 4-bit binary numbers
• Provides distinct active-high outputs for greater-than, less-than, and equal-to conditions
• Utilizes Low-power Schottky (LS) technology for optimized power-speed trade-off
• Supports cascading via dedicated input pins to expand comparison width

Comparators Applications

• Digital arithmetic logic units requiring magnitude determination
• Address decoding systems where address range validation is necessary
• Control logic circuits comparing setpoints against sensor values
• Data sorting hardware performing initial rank comparisons

Comparators Procurement Notes

Verify part status as obsolete or end-of-life before procurement planning. Confirm package compatibility with existing PCB footprints, specifically the 16-DIP format. Ensure voltage levels match system requirements for LS TTL inputs and outputs. Check for available direct replacements from other manufacturers if new production is required. Validate datasheet revisions for any pinout or electrical characteristic changes.

Comparators Selection Notes

Select this component when 4-bit magnitude comparison is required within a TTL-compatible logic family. Consider the LS series characteristics for applications needing lower power dissipation than standard 7400 series while maintaining adequate switching speeds. Evaluate cascading capabilities if comparisons involving more than four bits are necessary. Verify operating temperature range suitability for the intended environmental conditions.

Comparators Part Context

This component belongs to the widely adopted 7400 series of digital logic integrated circuits. Specifically, it falls under the 74LS (Low-power Schottky) sub-family, which was designed to improve upon the power efficiency of the original 7400 series without significant speed penalties. The DM prefix typically denotes a commercial grade variant offered by onsemi (formerly National Semiconductor). These comparators were foundational in early microprocessor systems and industrial control panels.

Comparators Replacement Considerations

Direct substitutes include equivalent 4-bit magnitude comparators from the 74LS85 family produced by other vendors such as Texas Instruments or NXP. Ensure replacement parts maintain identical pin configurations and logical functionality. Verify that alternative sources offer compatible packaging options if DIP-16 is mandatory.