SN74LS85DRE4

Overview

The SN74LS85DRE4 is a 4-bit magnitude comparator manufactured by Texas Instruments in the LS logic family. It operates within a supply voltage range of 4.75V to 5.25V and supports an operating temperature range of 0°C to 70°C. The device features active high outputs for A<B, A=B, and A>B conditions. It is housed in a 16-pin SOIC package with surface mount installation. Key electrical parameters include a maximum propagation delay of 27 ns at VCC=5V and a maximum supply current of 20 mA.

Feature Summary

• Performs 4-bit binary or BCD magnitude comparison between two input words
• Provides distinct active high outputs indicating less than, equal to, or greater than relationships
• Supports cascading via dedicated expand inputs for multi-bit comparisons

Applications

• Digital arithmetic logic units requiring magnitude evaluation
• Address decoding systems in microprocessor interfaces
• Control logic for sorting or ranking digital signals

Procurement Notes

Verify the component matches the specific SN74LS85DRE4 designation, noting the RE4 suffix indicates lead-free and RoHS compliance. Confirm the SOIC-16 package type and surface mount orientation. Ensure the supplier provides documentation confirming the active status and original manufacturer source to avoid counterfeit parts.

Selection Notes

Select this component when a standard TTL-compatible 4-bit comparator is required for surface mount designs. Consider the LS series speed and power characteristics relative to system constraints. Verify that the 16-pin SOIC footprint aligns with the PCB layout requirements and that the 0°C to 70°C commercial temperature range meets operational needs.

Part Context

This part belongs to the Texas Instruments SN74LSxx series of low-power Schottky logic devices. The SN74LS85 specifically functions as a magnitude comparator, distinguishing it from gates or flip-flops within the same family. It is designed for general-purpose digital logic applications requiring reliable comparison operations.

Replacement Considerations

The SN74LS85N is a pin-compatible through-hole alternative from Texas Instruments offering identical logical functionality.