SN74ACT240NS Equivalent & Substitute Parts

Part Overview

The SN74ACT240NS is a Buffer, Inverting logic integrated circuit manufactured by Texas Instruments, featuring 2 elements with 4 bits per element and 3-state output capability in a 20-SOIC package. This device operates within the 74ACT logic series and is classified as Last Time Buy, indicating discontinued production status. The part is ROHS3 compliant with unlimited moisture sensitivity rating (MSL 1). Due to its Last Time Buy status, identifying functionally equivalent substitute parts with active production status is essential for design continuity and long-term supply chain reliability.

Substiute Parts

SN74ACT240NS

Texas InstrumentsIn Stock: 784SN74ACT240NS Datasheet

Current PartRFQ

SN74ACT240NSR

Texas InstrumentsIn Stock: 3020SN74ACT240NSR Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SN74ACT240NS is determined by strict equivalence across the following critical parameters:

Functional Parameters: Logic type (Buffer, Inverting), number of elements (2), bits per element (4), and output configuration (3-State) must remain identical.

Electrical Parameters: Supply voltage range (4.5V ~ 5.5V), output current specifications (24mA high and low), and operating temperature range (-40°C ~ 85°C) must be maintained.

Physical Parameters: Package type (20-SOIC) and mounting method (Surface Mount) must match to ensure PCB compatibility without redesign.

Compliance Parameters: RoHS3 compliance and MSL rating (1) must be preserved for manufacturing and environmental requirements.

The SN74ACT240NSR qualifies as a direct substitute based on complete alignment across all these parameters, with the distinction that it maintains active production status and is available in Tape & Reel packaging.

Parameter Comparison

Engineering Selection Recommendations

The SN74ACT240NSR is the direct functional equivalent of the SN74ACT240NS and is suitable for substitution in all applications where the main part was specified. Both parts are manufactured by Texas Instruments within the 74ACT logic series and maintain identical electrical, functional, and physical characteristics.

Primary Advantage: The SN74ACT240NSR maintains Active product status, ensuring continued availability and supply chain stability, whereas the SN74ACT240NS is designated Last Time Buy with limited future procurement options.

Compliance Alignment: Both parts are ROHS3 compliant with MSL 1 rating, meeting environmental and manufacturing requirements without modification.

Packaging Consideration: The SN74ACT240NSR is supplied in Tape & Reel format, which is standard for high-volume production environments. The SN74ACT240NS is supplied in tube packaging. Selection between these packaging formats depends on assembly line requirements and order quantities.

No Design Changes Required: The identical 20-SOIC package footprint and electrical specifications eliminate the need for PCB redesign or circuit modification.

Frequently Asked Questions (FAQ)

Q: Can the SN74ACT240NSR directly replace the SN74ACT240NS without PCB modification?

A: Yes. Both parts use the identical 20-SOIC package with 0.209" width and 5.30mm dimensions. No PCB layout changes are required for substitution.

Q: Are the electrical specifications identical between these parts?

A: Yes. Both parts operate at 4.5V to 5.5V supply voltage, deliver 24mA output current (high and low), and function across the -40°C to 85°C temperature range. Logic function, element count, and bit configuration are identical.

Q: Why is the SN74ACT240NS marked as Last Time Buy?

A: Last Time Buy designation indicates that Texas Instruments has discontinued production of this part number. Existing inventory is available for final orders, but no future production is planned. The SN74ACT240NSR remains in active production.

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

A: Tube packaging contains loose components suitable for manual handling and small-quantity orders. Tape & Reel packaging is designed for automated pick-and-place assembly equipment and is standard for production environments. Both formats contain identical components.

Q: Are both parts RoHS3 compliant?

A: Yes. Both the SN74ACT240NS and SN74ACT240NSR are ROHS3 compliant with MSL 1 (unlimited moisture sensitivity), meeting environmental and manufacturing standards.

Q: Can I use the SN74ACT240NSR in existing designs specified for SN74ACT240NS?

A: Yes. The SN74ACT240NSR is a direct functional equivalent with no design modifications required. It is suitable for new production runs and design revisions.