SN74LS85D Magnitude Comparator - Equivalent & Substitute Parts

Part Overview

The SN74LS85D is a 4-bit magnitude comparator logic IC manufactured by Texas Instruments, housed in a 16-SOIC surface mount package. This component performs binary comparison operations, providing active-high outputs for A<B, A=B, and A>B conditions. The SN74LS85D is currently in Last Time Buy status, indicating discontinued production. Identifying equivalent substitute parts is necessary to ensure design continuity and maintain supply chain reliability for new production runs or inventory replenishment.

Substiute Parts

SN74LS85D

Texas InstrumentsIn Stock: 2919SN74LS85D Datasheet

Current PartRFQ

SN74LS85DR

Texas InstrumentsIn Stock: 5390SN74LS85DR Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SN74LS85D is determined by strict equivalence across the following critical parameters:

• Functional Equivalence: Identical 4-bit magnitude comparator architecture with active-high A<B, A=B, A>B outputs
• Electrical Specifications: Matching supply voltage range (4.75V ~ 5.25V), output current ratings (400µA high, 8mA low), and propagation delay (45ns @ 5V, 15pF)
• Package Compatibility: Identical 16-SOIC surface mount package with 0.154" (3.90mm) width
• Thermal Performance: Identical operating temperature range (0°C ~ 70°C)
• Regulatory Compliance: ROHS3 compliance, REACH unaffected status, and MSL 1 rating

The SN74LS85DR qualifies as a direct substitute based on complete alignment with all electrical, mechanical, and regulatory parameters. The primary distinction is packaging format: the SN74LS85D is supplied in Tube packaging, while the SN74LS85DR is supplied in Tape & Reel (TR) format. Both share identical die and performance characteristics.

Parameter Comparison

Engineering Selection Recommendations

The SN74LS85DR is the direct substitute for the SN74LS85D. Selection between these parts should be based on the following criteria:

SN74LS85D (Tube Packaging): Select when existing inventory in tube format is available or when manual component handling and small-quantity assembly processes are employed. Current product status is Last Time Buy, indicating limited future availability.

SN74LS85DR (Tape & Reel Packaging): Select for new designs, production ramp-up, or high-volume manufacturing requiring automated pick-and-place assembly. This part maintains Active product status with Texas Instruments, ensuring long-term supply chain stability and availability. Tape & Reel format is optimized for surface mount assembly lines.

Both parts carry identical ROHS3 compliance and REACH unaffected certifications, confirming regulatory equivalence for applications requiring environmental compliance documentation.

Frequently Asked Questions (FAQ)

Q: Can the SN74LS85DR directly replace the SN74LS85D in existing designs?

A: Yes. The SN74LS85DR is electrically and functionally identical to the SN74LS85D. Both parts share the same die, pin configuration, electrical specifications, and 16-SOIC package dimensions. The only difference is the packaging format (Tape & Reel versus Tube).

Q: What is the difference between Tube and Tape & Reel packaging?

A: Tube packaging supplies components in plastic tubes suitable for manual handling and small-quantity assembly. Tape & Reel packaging supplies components on continuous carrier tape wound on reels, optimized for automated surface mount assembly equipment. Both formats contain identical components with no electrical differences.

Q: Is the SN74LS85DR suitable for high-volume production?

A: Yes. The Tape & Reel format of the SN74LS85DR is specifically designed for automated assembly processes and high-volume manufacturing. The Active product status ensures consistent availability from Texas Instruments.

Q: Are there any thermal or performance differences between these parts?

A: No. Both the SN74LS85D and SN74LS85DR operate identically across the full temperature range (0°C ~ 70°C) with identical propagation delay specifications (45ns @ 5V, 15pF) and output current ratings.

Q: What should I consider when transitioning from SN74LS85D to SN74LS85DR?

A: The transition is straightforward from an engineering perspective. Verify that your assembly process can accommodate Tape & Reel format if switching from Tube packaging. Both parts are ROHS3 compliant and REACH unaffected, requiring no design or compliance documentation changes.