SN74LS240NS Equivalent & Substitute Parts

Part Overview

The SN74LS240NS is a Buffer, Inverting logic IC manufactured by Texas Instruments, featuring 2 elements with 4 bits per element and 3-state output capability. This component operates within the 4.75V to 5.25V supply voltage range and is housed in a 20-SOIC package. The SN74LS240NS is classified as Last Time Buy, indicating discontinued production. Identifying equivalent substitute parts is necessary to ensure design continuity and maintain supply chain reliability for applications currently utilizing this component.

Substiute Parts

SN74LS240NS

Texas InstrumentsIn Stock: 1070SN74LS240NS Datasheet

Current PartRFQ

SN74LS240NSR

Texas InstrumentsIn Stock: 3482SN74LS240NSR Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the SN74LS240NS are determined by equivalence across the following critical parameters:

• Logic Type: Buffer, Inverting
• Number of Elements: 2
• Number of Bits per Element: 4
• Output Type: 3-State
• Current Ratings: 15mA (High), 24mA (Low)
• Supply Voltage Range: 4.75V ~ 5.25V
• Operating Temperature Range: 0°C ~ 70°C
• Package / Case: 20-SOIC (0.209", 5.30mm Width)
• Mounting Type: Surface Mount
• RoHS and REACH Compliance Status

The SN74LS240NSR is identified as a manufacturer-recommended substitute, maintaining identical electrical specifications and package configuration while differing only in packaging format (Tape & Reel versus Tube) and product status (Active versus Last Time Buy).

Parameter Comparison

Engineering Selection Recommendations

The SN74LS240NSR is the direct functional equivalent of the SN74LS240NS. Both components share identical electrical characteristics, pin configuration, and package specifications. The primary distinction is product status: the SN74LS240NS is designated Last Time Buy, while the SN74LS240NSR maintains Active status with higher inventory availability (3460 units versus 987 units).

For new designs or replenishment of existing applications, the SN74LS240NSR is the appropriate selection due to its active production status and sustained supply chain availability. Both variants maintain full ROHS3 compliance and REACH unaffected status, ensuring regulatory alignment for industrial and commercial applications.

Frequently Asked Questions (FAQ)

Q: Are the SN74LS240NS and SN74LS240NSR electrically identical?

A: Yes. Both components feature identical logic type, element count, bit configuration, output type, current ratings, supply voltage range, and operating temperature specifications. They are functionally interchangeable at the circuit level.

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

A: Tube packaging (SN74LS240NS) is suitable for manual handling and smaller quantity orders. Tape & Reel packaging (SN74LS240NSR) is designed for automated assembly processes and high-volume production. The electrical and mechanical specifications of the component itself remain unchanged.

Q: Why is the SN74LS240NS marked as Last Time Buy?

A: Last Time Buy designation indicates that the manufacturer has discontinued production of this specific packaging variant. The SN74LS240NSR, with identical specifications in Tape & Reel format, remains in active production and is the recommended alternative for ongoing supply requirements.

Q: Can I use the SN74LS240NSR as a direct replacement in existing PCB designs?

A: Yes. The SN74LS240NSR is pin-compatible and functionally equivalent. No circuit modifications are required. The only consideration is the packaging format change from Tube to Tape & Reel, which affects procurement and assembly processes, not circuit performance.

Q: Are both parts compliant with current regulatory standards?

A: Yes. Both the SN74LS240NS and SN74LS240NSR are ROHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements for industrial and commercial applications.