SN74ALS240ANS Equivalent & Substitute Parts

Part Overview

The SN74ALS240ANS is a Buffer, Inverting logic integrated circuit manufactured by Texas Instruments. This device features 2 elements with 4 bits per element and 3-state output capability in a 20-SOIC surface mount package. The part is classified as Last Time Buy, indicating discontinued production status. Identification of equivalent and substitute parts is necessary to ensure continued design support, maintain supply chain continuity, and facilitate component procurement for new production runs or design revisions.

Substiute Parts

SN74ALS240ANS

Texas InstrumentsIn Stock: 1998SN74ALS240ANS Datasheet

Current PartRFQ

SN74ALS240A-1NSR

Texas InstrumentsIn Stock: 3184SN74ALS240A-1NSR Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SN74ALS240ANS is determined by strict equivalence across the following critical parameters:

Functional Parameters:

• Logic type: Buffer, Inverting
• Element configuration: 2 elements, 4 bits per element
• Output configuration: 3-State

Electrical Parameters:

• Output current specifications: 15mA (high), 48mA (low)
• Supply voltage range: 4.5V ~ 5.5V
• Operating temperature range: 0°C ~ 70°C

Physical Parameters:

• Package type: 20-SOIC with 0.209" (5.30mm) width
• Mounting type: Surface mount

Compliance Parameters:

• RoHS3 compliance
• Moisture sensitivity level: 1 (Unlimited)

The SN74ALS240A-1NSR qualifies as a direct substitute based on identical functional, electrical, and physical specifications. The primary distinction is product status and packaging format.

Parameter Comparison

Engineering Selection Recommendations

The SN74ALS240A-1NSR is the direct substitute for the SN74ALS240ANS. Selection of this substitute is supported by the following factors:

Product Status: The SN74ALS240ANS carries Last Time Buy status, indicating end-of-life production. The SN74ALS240A-1NSR maintains Active product status, ensuring continued availability and manufacturing support from Texas Instruments.

Compliance Certification: Both parts maintain ROHS3 compliance and identical moisture sensitivity ratings, satisfying regulatory and environmental requirements without modification to existing designs.

Functional Equivalence: Electrical and functional specifications are identical across all critical parameters, including logic type, element configuration, output characteristics, supply voltage range, and operating temperature range.

Physical Compatibility: Both parts utilize the 20-SOIC package with identical dimensions, enabling direct board-level substitution without PCB redesign.

Packaging Consideration: The SN74ALS240A-1NSR is supplied in Tape & Reel format, which is standard for production volume applications, whereas the SN74ALS240ANS is supplied in prototype packaging. This distinction reflects typical manufacturing and distribution practices rather than functional differences.

Frequently Asked Questions (FAQ)

Q: Can the SN74ALS240A-1NSR be used as a direct replacement for the SN74ALS240ANS in existing designs?

A: Yes. The SN74ALS240A-1NSR is functionally and electrically equivalent to the SN74ALS240ANS. All critical parameters including logic type, element configuration, output current specifications, supply voltage range, operating temperature range, and package dimensions are identical. Direct substitution is supported without circuit modification.

Q: What is the difference between the SN74ALS240ANS and SN74ALS240A-1NSR?

A: The primary differences are product status and packaging format. The SN74ALS240ANS is Last Time Buy (discontinued), while the SN74ALS240A-1NSR is Active (currently manufactured). The SN74ALS240ANS is supplied in prototype packaging, while the SN74ALS240A-1NSR is supplied in Tape & Reel format for production applications. Functional and electrical specifications are identical.

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

A: No. Both parts maintain ROHS3 compliance and identical moisture sensitivity level ratings (MSL 1 - Unlimited). No additional certifications or compliance modifications are required when substituting between these parts.

Q: Is the 20-SOIC package identical for both parts?

A: Yes. Both parts use the 20-SOIC package with identical dimensions (0.209" width, 5.30mm). PCB footprints and board-level placement are fully compatible.

Q: Why is the SN74ALS240ANS marked as Last Time Buy?

A: Last Time Buy status indicates that Texas Instruments has discontinued production of this specific part number variant. The SN74ALS240A-1NSR represents the active production equivalent and is the recommended part for new designs and ongoing production requirements.

Q: What inventory considerations should be evaluated when transitioning from SN74ALS240ANS to SN74ALS240A-1NSR?

A: The SN74ALS240ANS has 1900 pieces available in stock, while the SN74ALS240A-1NSR has 3155 pieces available. The SN74ALS240A-1NSR offers greater inventory availability and ongoing supply assurance due to its Active product status.