SN74ALS257AD Equivalent & Substitute Parts

Part Overview

The SN74ALS257AD is a 4 x 2:1 multiplexer logic integrated circuit manufactured by Texas Instruments in 16-SOIC surface mount packaging. This component functions as a data selector, routing one of two input signals to a single output based on control logic. The SN74ALS257AD is classified as Last Time Buy, indicating discontinued production status. Identifying equivalent substitute parts is necessary to ensure design continuity and maintain supply chain reliability for applications currently utilizing this component.

Substiute Parts

SN74ALS257AD

Texas InstrumentsIn Stock: 1275SN74ALS257AD Datasheet

Current PartRFQ

SN74ALS257ADR

Texas InstrumentsIn Stock: 3708SN74ALS257ADR Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the SN74ALS257AD is determined by strict equivalence across the following critical parameters:

• Circuit configuration: 4 x 2:1 multiplexer topology
• Package type: 16-SOIC surface mount form factor
• Electrical specifications: Voltage supply range 4.5V ~ 5.5V, output current ratings 2.6mA (high) and 24mA (low)
• Operating temperature range: 0°C ~ 70°C
• Compliance certifications: ROHS3, REACH Unaffected status
• Base product series: 74ALS

The SN74ALS257ADR qualifies as a direct substitute based on identical electrical performance, package geometry, and regulatory compliance. The primary distinction is packaging format: the SN74ALS257AD ships in Tube packaging, while the SN74ALS257ADR is supplied in Tape & Reel (TR) format. Both components share the same silicon die and electrical characteristics.

Parameter Comparison

Engineering Selection Recommendations

The SN74ALS257ADR is the direct equivalent substitute for the SN74ALS257AD. Both components are manufactured by Texas Instruments and maintain identical electrical specifications, package dimensions, and regulatory compliance certifications (ROHS3 Compliant, REACH Unaffected).

The SN74ALS257ADR holds Active product status, ensuring continued availability and manufacturing support, whereas the SN74ALS257AD is Last Time Buy. Selection of the SN74ALS257ADR eliminates obsolescence risk while preserving full functional and mechanical compatibility.

The packaging format difference (Tube versus Tape & Reel) does not affect electrical performance or PCB assembly compatibility. This distinction is relevant only to procurement and handling procedures.

Frequently Asked Questions (FAQ)

Q: Can the SN74ALS257ADR directly replace the SN74ALS257AD in existing designs?

A: Yes. The SN74ALS257ADR is electrically and mechanically equivalent. Both components feature identical 16-SOIC package geometry, electrical ratings, and pin configuration. No design modifications are required.

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

A: Tube and Tape & Reel are packaging and delivery formats that do not affect component performance. Tube packaging is used for manual handling and smaller quantities. Tape & Reel format is optimized for automated assembly processes and bulk quantities. The silicon die and electrical specifications are identical.

Q: Why is the SN74ALS257AD marked as Last Time Buy?

A: Last Time Buy status indicates that Texas Instruments has discontinued production of this specific part number. The SN74ALS257ADR remains in Active production and serves as the recommended alternative for new designs and replenishment orders.

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

A: No. Both the SN74ALS257AD and SN74ALS257ADR carry identical ROHS3 Compliance and REACH Unaffected certifications. Regulatory compliance is maintained across both part numbers.

Q: What is the Moisture Sensitivity Level (MSL) rating?

A: Both components carry MSL 1 (Unlimited), indicating the lowest moisture sensitivity classification. These parts do not require special moisture control during storage or handling.