SN74LS51D Equivalent & Substitute Parts

Part Overview

The SN74LS51D is a 14-pin surface-mount AND/OR/INVERT gate logic integrated circuit manufactured by Texas Instruments. This component features two configurable circuits with 10 total inputs (3, 3, 2, 2 configuration) and single-ended output. The device operates within the 4.75V to 5.25V supply voltage range and is rated for 0°C to 70°C operating temperature. Currently classified as Last Time Buy status, identifying equivalent substitute parts is essential for design continuity and long-term component availability.

Substiute Parts

SN74LS51D

Texas InstrumentsIn Stock: 3618SN74LS51D Datasheet

Current PartRFQ

SN74LS51DR

Texas InstrumentsIn Stock: 1245SN74LS51DR Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SN74LS51D is determined by strict equivalence across the following critical parameters:

• Logic function: AND/OR/INVERT gate configuration with identical circuit count (2) and input distribution (3, 3, 2, 2)
• Electrical specifications: Output current ratings (400µA high, 8mA low), supply voltage range (4.75V ~ 5.25V), and operating temperature (0°C ~ 70°C)
• Package specification: 14-SOIC surface-mount package with 0.154" (3.90mm) width
• Compliance certifications: ROHS3 compliance, MSL Level 1, and REACH unaffected status

The SN74LS51DR qualifies as a direct substitute based on identical electrical performance, package form factor, and regulatory compliance. The primary distinction is packaging format: the SN74LS51D is supplied in Tube packaging, while the SN74LS51DR is supplied in Tape & Reel (TR) format. Both devices share the same base product number (74LS51) and are manufactured by Texas Instruments.

Parameter Comparison

Engineering Selection Recommendations

The SN74LS51DR is the manufacturer-recommended substitute for the SN74LS51D. Both devices are manufactured by Texas Instruments and maintain identical electrical performance, functional configuration, and regulatory compliance status. The SN74LS51D is designated Last Time Buy, indicating discontinued production; the SN74LS51DR maintains Active product status and is the appropriate long-term replacement.

Selection between these parts is determined by packaging requirements. The SN74LS51D is supplied in Tube packaging, suitable for lower-volume applications and manual assembly processes. The SN74LS51DR is supplied in Tape & Reel format, optimized for automated pick-and-place assembly and higher-volume production environments. Both devices are ROHS3 compliant, MSL Level 1 rated, and REACH unaffected, meeting current regulatory requirements for electronic component manufacturing and distribution.

Frequently Asked Questions (FAQ)

Q: Can the SN74LS51DR directly replace the SN74LS51D in existing designs?

A: Yes. The SN74LS51DR is electrically and functionally identical to the SN74LS51D. Both devices feature the same AND/OR/INVERT gate configuration, output current ratings, supply voltage range, and operating temperature specifications. The 14-SOIC package dimensions are identical, enabling direct PCB-level substitution without design modification.

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

A: Tube packaging supplies individual components in a plastic tube, typically used for lower-volume orders and manual assembly. Tape & Reel packaging supplies components on continuous carrier tape wound on reels, optimized for automated assembly equipment. Both formats contain the same component; packaging selection depends on assembly process requirements and order volume.

Q: Why is the SN74LS51D classified as Last Time Buy?

A: Last Time Buy status indicates that Texas Instruments has discontinued production of this part number. Existing inventory may be available for a limited time, but no new production runs are scheduled. The SN74LS51DR, with Active product status, is the designated replacement for ongoing designs and future production.

Q: Are there any compliance or certification differences between these parts?

A: No. Both the SN74LS51D and SN74LS51DR maintain identical ROHS3 compliance, MSL Level 1 rating, and REACH unaffected status. Both devices meet current regulatory requirements for electronic component manufacturing and distribution.

Q: What inventory considerations apply to these parts?

A: The SN74LS51D has 3530 pieces in stock (Last Time Buy status). The SN74LS51DR has 1150 pieces in stock (Active status). For new designs and long-term production, the SN74LS51DR is the recommended selection due to its Active product status and ongoing availability.