74F240SC Equivalent & Substitute Parts

Part Overview

The 74F240SC is an inverting buffer logic integrated circuit manufactured by onsemi, designed for 5.5V operation with 2 elements and 4 bits per element, featuring 3-state output capability in a 20-SOIC package. The part is currently obsolete, making equivalent substitutes necessary for ongoing design support and procurement. The 74F240 series provides standard TTL-compatible buffering functionality suitable for digital logic applications requiring signal inversion and tri-state control.

Substiute Parts

74F240SC

onsemiIn Stock: 84674F240SC Datasheet

Current PartRFQ

SN74F240DW

Texas InstrumentsIn Stock: 1521SN74F240DW Datasheet

DirectRFQ

SN74F240DWR

Texas InstrumentsIn Stock: 2153SN74F240DWR Datasheet

DirectRFQ

SN74F240NSR

Texas InstrumentsIn Stock: 3274SN74F240NSR Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the 74F240SC is determined by strict equivalence across the following parameters: logic type (inverting buffer), element count (2), bits per element (4), output type (3-state), supply voltage range (4.5V ~ 5.5V), operating temperature range (0°C ~ 70°C), and package compatibility (20-SOIC or mechanically equivalent 20-SO).

Direct substitutes maintain identical electrical specifications and package footprints. Similar substitutes maintain electrical equivalence but differ in package dimensions, requiring PCB layout verification before implementation.

Parameter Comparison

Engineering Selection Recommendations

SN74F240DWR (Texas Instruments) is the primary substitute for the obsolete 74F240SC. This part maintains active product status, ensuring long-term availability and supply chain stability. It is ROHS3 compliant and electrically equivalent across all critical parameters. The output high current specification (15mA versus 3mA in the original) provides improved drive capability without compromising circuit compatibility.

SN74F240DW (Texas Instruments) serves as an alternative direct substitute with identical electrical and package specifications. This part carries Last Time Buy status, indicating limited future availability; selection should prioritize SN74F240DWR for new designs.

SN74F240NSR (Texas Instruments) is electrically equivalent but features a narrower 20-SO package (5.30mm width versus 7.50mm width). This part is suitable only for applications where PCB layout accommodates the reduced package width. Active product status ensures availability.

Frequently Asked Questions (FAQ)

Q: Can SN74F240DWR directly replace 74F240SC without PCB modifications?

A: Yes. SN74F240DWR maintains identical pin configuration, package footprint (20-SOIC 0.295" width), and electrical specifications within the specified operating range. No PCB layout changes are required.

Q: What is the significance of the output high current difference (3mA vs. 15mA)?

A: The 74F240SC specifies 3mA output high current, while Texas Instruments substitutes specify 15mA. This difference indicates improved drive capability in the substitute parts. Circuits designed for the original 3mA specification will operate correctly with the higher current rating, as it represents enhanced performance rather than a limitation.

Q: Is SN74F240NSR compatible with existing PCB designs?

A: SN74F240NSR is electrically compatible but differs in package width (5.30mm versus 7.50mm). PCB footprints designed for the standard 20-SOIC package may not accommodate this narrower variant. Verify PCB layout spacing before selection.

Q: Why is 74F240SC obsolete?

A: The 74F240SC has reached end-of-life status. Texas Instruments actively manufactures equivalent parts (SN74F240DWR, SN74F240DW, SN74F240NSR) that provide superior availability and compliance certifications.

Q: Are all substitutes ROHS3 compliant?

A: Yes. All Texas Instruments substitutes (SN74F240DW, SN74F240DWR, SN74F240NSR) are ROHS3 compliant. The original 74F240SC RoHS status was not specified in available documentation.