74F240SJ Equivalent & Substitute Parts

Part Overview

The 74F240SJ is an inverting buffer logic integrated circuit manufactured by onsemi, featuring 2 elements with 4 bits per element and 3-state output capability. This component is classified as obsolete, which necessitates identification of equivalent and substitute parts for ongoing design requirements and production continuity. The 74F240 series provides standard logic buffering functionality with inverted output configuration suitable for digital signal conditioning applications.

Substiute Parts

74F240SJ

onsemiIn Stock: 169374F240SJ Datasheet

Current PartRFQ

SN74F240NSR

Texas InstrumentsIn Stock: 3274SN74F240NSR Datasheet

DirectRFQ

SN74F240DW

Texas InstrumentsIn Stock: 1521SN74F240DW Datasheet

SimilarRFQ

SN74F240DWR

Texas InstrumentsIn Stock: 2153SN74F240DWR Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 74F240SJ is determined by the following critical parameters that must remain consistent across equivalent parts:

• Logic Type: Buffer, Inverting configuration
• Number of Elements: 2 elements
• Number of Bits per Element: 4 bits
• Output Type: 3-State output capability
• Voltage - Supply: 4.5V ~ 5.5V operating range
• Operating Temperature: 0°C ~ 70°C (TA)
• Mounting Type: Surface Mount
• Base Product Number: 74F240 series

The substitute parts identified maintain these core functional and electrical parameters. Variations in output current specifications (3mA vs. 15mA for output high current) and package dimensions remain within acceptable substitution criteria for the 74F logic family. Product status differences (Active vs. Obsolete vs. Last Time Buy) reflect current market availability and manufacturing continuity.

Parameter Comparison

Engineering Selection Recommendations

For applications currently using the 74F240SJ, the following selection criteria apply based on product status and compliance:

Primary Recommendation: SN74F240DWR (Texas Instruments)

The SN74F240DWR is the preferred substitute, maintaining Active product status with ROHS3 compliance. This part provides current manufacturing availability and long-term supply continuity. The increased output high current specification (15mA vs. 3mA) represents an enhancement in drive capability without compromising circuit compatibility in standard 74F logic applications.

Secondary Option: SN74F240NSR (Texas Instruments)

The SN74F240NSR offers Active product status with ROHS3 compliance and maintains the narrower package width (0.209", 5.30mm) matching the original 74F240SJ footprint. This option is suitable when PCB layout constraints require minimal package dimensions.

Alternative: SN74F240DW (Texas Instruments)

The SN74F240DW carries Last Time Buy status, indicating limited future availability. This part should be considered only when existing inventory requirements or specific design constraints necessitate the wider package configuration (0.295", 7.50mm).

All three substitute parts maintain electrical equivalence within the 74F logic family specifications and support identical functional integration.

Frequently Asked Questions (FAQ)

Q: Can the SN74F240NSR directly replace the 74F240SJ in existing designs?

A: Yes. Both parts maintain identical logic type, element count, bit configuration, output type, supply voltage range, and operating temperature specifications. The primary difference is the increased output high current (15mA vs. 3mA), which provides enhanced drive capability without requiring circuit modifications.

Q: What is the significance of the package width difference between the 74F240SJ and SN74F240DW?

A: The 74F240SJ uses a 20-SOIC package with 0.209" width, while the SN74F240DW uses 0.295" width. Both are 20-pin SOIC packages with identical pin configurations. The width difference affects PCB footprint spacing but does not impact electrical functionality. Verify PCB layout compatibility before substitution.

Q: Why does the SN74F240DWR have higher output current specifications than the 74F240SJ?

A: The output high current specification differs (15mA vs. 3mA), while output low current remains identical (64mA). This represents a design improvement in the Texas Instruments version, providing greater output drive capability. This enhancement is compatible with standard 74F logic applications and does not require circuit redesign.

Q: Are all substitute parts RoHS compliant?

A: Yes. The SN74F240NSR, SN74F240DW, and SN74F240DWR are all ROHS3 compliant. The original 74F240SJ RoHS status was not specified in the provided data.

Q: Which substitute part offers the best long-term availability?

A: The SN74F240DWR maintains Active product status, indicating current manufacturing and ongoing availability. The SN74F240NSR also maintains Active status. The SN74F240DW carries Last Time Buy status, indicating limited future production.

Q: Are there any thermal or environmental differences between these parts?

A: All parts operate within identical temperature ranges (0°C ~ 70°C TA) and maintain MSL 1 (Unlimited) moisture sensitivity levels. No thermal or environmental performance differences exist between the main part and substitutes.