SN74LS85DR

Overview

The SN74LS85DR is a 4-bit magnitude comparator from Texas Instruments' 74LS logic series. It performs binary or BCD comparison between two 4-bit words (A and B). The device features three active-high outputs indicating A>B, A<B, or A=B. It operates at a nominal voltage of 5V with a range of 4.75V to 5.25V. Packaged in a 16-SOIC surface-mount format, it supports an operating temperature range of 0°C to 70°C.

Feature Summary

• Executes pure binary and BCD magnitude comparisons for two 4-bit inputs
• Provides three fully decoded active-high outputs for inequality and equality states
• Directly compatible with TTL and CMOS inputs above 2.0V threshold levels

Applications

• Digital data comparison circuits
• BCD code validation systems
• Magnitude decision logic in control units

Procurement Notes

Verify the specific suffix 'DR' confirms the tape-and-reel packaging variant rather than the tube version. Confirm the 74LS logic family compatibility requirements with your system's power supply and input thresholds. Ensure the 16-SOIC footprint matches your PCB design constraints before finalizing procurement orders.

Selection Notes

Select this component when 4-bit magnitude comparison is required within standard 5V TTL/CMOS environments. Consider the 74LS series speed and power characteristics against alternatives if lower power consumption or higher switching speeds are critical for the specific application design.

Part Context

This part belongs to the Texas Instruments 74LS series of logic comparators. It serves as a fundamental building block for digital arithmetic and decision-making circuits. The DR suffix indicates a specific surface-mount packaging configuration suitable for automated assembly processes.

Replacement Considerations

The SN74LS85DRG4 is a verified equivalent part number offering identical functionality and specifications. Verify pinout and electrical parameters match exactly when substituting.