SN74ALS27AD Equivalent & Substitute Parts

Part Overview

The SN74ALS27AD is a NOR Gate IC featuring 3 channels with 3 inputs per channel in a 14-SOIC surface mount package, manufactured by Texas Instruments. This component is classified as Last Time Buy, indicating limited availability and the necessity to identify equivalent alternatives for ongoing production requirements. The SN74ALS27AD operates within the 74ALS logic family and is suitable for digital logic applications requiring NOR gate functionality in compact form factors.

Substiute Parts

SN74ALS27AD

Texas InstrumentsIn Stock: 1277SN74ALS27AD Datasheet

Current PartRFQ

SN74ALS27ADR

Texas InstrumentsIn Stock: 964SN74ALS27ADR Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SN74ALS27AD is determined by strict equivalence across the following critical parameters:

• Logic Type: NOR Gate configuration with identical channel and input count (3 channels, 3 inputs per channel)
• Electrical Specifications: Matching supply voltage range (4.5V ~ 5.5V), output current ratings (400µA, 8mA), input logic levels (0.8V low, 2V high), and propagation delay (15ns @ 5V, 50pF)
• Package Compatibility: 14-SOIC surface mount package with identical physical dimensions (0.154", 3.90mm Width)
• Operating Temperature Range: 0°C ~ 70°C
• Compliance Standards: ROHS3 Compliant, MSL Level 1

The SN74ALS27ADR qualifies as a direct substitute based on identical electrical and mechanical parameters. The distinction between these parts lies in packaging format: the main part (SN74ALS27AD) is supplied in Tube packaging, while the substitute (SN74ALS27ADR) is supplied in Tape & Reel format. Both parts share the same base product number (74ALS27) and are manufactured by Texas Instruments.

Parameter Comparison

Engineering Selection Recommendations

The SN74ALS27AD is designated as Last Time Buy, making the SN74ALS27ADR the recommended alternative for new designs and ongoing production. Both parts maintain identical electrical performance and package specifications, ensuring direct functional compatibility.

The SN74ALS27ADR carries Active product status, confirming continued manufacturer support and availability. Both parts satisfy ROHS3 compliance requirements and maintain MSL Level 1 rating, indicating no moisture sensitivity constraints during storage and handling.

Selection between these parts should be based on procurement requirements: Tube packaging (SN74ALS27AD) is suitable for lower-volume applications, while Tape & Reel packaging (SN74ALS27ADR) is optimized for automated assembly processes and higher-volume production runs.

Frequently Asked Questions (FAQ)

Q: Can the SN74ALS27ADR directly replace the SN74ALS27AD in existing designs?

A: Yes. The SN74ALS27ADR is a direct functional equivalent with identical electrical specifications, logic configuration, and 14-SOIC package dimensions. No circuit modifications are required.

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

A: Tube packaging supplies individual components in plastic tubes, suitable for manual assembly and lower-volume applications. Tape & Reel packaging supplies components on continuous tape for automated pick-and-place assembly systems. Both formats contain the same component with identical specifications.

Q: Why is the SN74ALS27AD marked as Last Time Buy?

A: Last Time Buy designation indicates that the manufacturer will discontinue production of this specific part number. The SN74ALS27ADR remains in active production and should be used for new designs and future procurement.

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

A: No. Both parts are ROHS3 Compliant, carry identical MSL Level 1 ratings, and meet the same environmental and regulatory standards.

Q: What are the critical parameters for substitution compatibility?

A: Substitution compatibility is determined by matching logic type (NOR Gate, 3 channels, 3 inputs), supply voltage (4.5V ~ 5.5V), output current ratings (400µA, 8mA), input logic levels (0.8V low, 2V high), propagation delay (15ns @ 5V, 50pF), operating temperature range (0°C ~ 70°C), and 14-SOIC package format.