SN74LS85NSR

Overview

The SN74LS85NSR is a 4-bit binary or BCD magnitude comparator manufactured by Texas Instruments in the SOIC-16 package. It performs logical comparisons to determine if input A is less than, equal to, or greater than input B. Key electrical parameters include a propagation delay of 24 ns and 27 ns, a maximum supply current of 20 mA, and an operating voltage range of 4.75 V to 5.25 V. The device supports active high outputs and operates within a temperature range of 0°C to +70°C.

Feature Summary

• Performs 4-bit magnitude comparison for binary or BCD inputs
• Provides active high outputs for A<B, A=B, and A>B conditions
• Supports cascading for multi-bit expansion

Applications

• Digital arithmetic logic units
• Address decoding systems
• Control logic circuits

Procurement Notes

Verify the specific suffix 'SR' indicates the tape and reel packaging variant distinct from the tube-packaged 'N' version. Confirm the SOIC-16 footprint matches the target PCB design. Ensure the LS logic family compatibility aligns with existing system voltage and speed requirements before finalizing procurement.

Selection Notes

Select this component when a 4-bit magnitude comparison function is required in a surface-mount application. The LS series offers standard TTL compatibility with moderate speed. Consider the SOIC-16 package for space-constrained designs requiring through-hole equivalent functionality in a smaller form factor.

Part Context

This part belongs to the Texas Instruments SN74LSxx series of low-power Schottky logic devices. It is functionally equivalent to other 4-bit comparators in the industry but is specifically identified by the TI part number SN74LS85NSR. The 'SR' suffix denotes the reel packaging format used for automated assembly processes.

Replacement Considerations

Direct substitutes include the SN74LS85N (tube package) and SN74LS85NSR (reel package). Cross-brand equivalents such as the MC74LS85P may be considered if pin-compatible and electrically verified.