74AC240SC Equivalent & Substitute Parts

Part Overview

The 74AC240SC is a Buffer, Inverting logic IC manufactured by onsemi, featuring 2 elements with 4 bits per element and 3-state output capability in a 20-SOIC package. This part is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement continuity. The 74AC240 series provides standard inverting buffer functionality across multiple manufacturers and packaging options.

Substiute Parts

74AC240SC

onsemiIn Stock: 105474AC240SC Datasheet

Current PartRFQ

MC74AC240DWG

onsemiIn Stock: 1190MC74AC240DWG Datasheet

DirectRFQ

MC74AC240DWR2G

onsemiIn Stock: 1040MC74AC240DWR2G Datasheet

SimilarRFQ

SN74AC240DWR

Texas InstrumentsIn Stock: 2789SN74AC240DWR Datasheet

DirectRFQ

CD74AC240M

Harris CorporationIn Stock: 23933CD74AC240M Datasheet

SimilarRFQ

CD74AC240M96

Texas InstrumentsIn Stock: 2194CD74AC240M96 Datasheet

SimilarRFQ

SN74AC240NSR

Texas InstrumentsIn Stock: 3433SN74AC240NSR Datasheet

SimilarRFQ

SN74AC240DW

Texas InstrumentsIn Stock: 1829SN74AC240DW Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the 74AC240SC is determined by strict equivalence in the following parameters:

• Logic Type: Buffer, Inverting
• Number of Elements: 2
• Number of Bits per Element: 4
• Output Type: 3-State
• Operating Temperature Range: -40°C ~ 85°C (TA)
• Supply Voltage Range: Must encompass or match 2V ~ 6V
• Output Current Capability: 24mA minimum for both high and low states
• Package / Case: 20-SOIC form factor
• Mounting Type: Surface Mount

Substitute parts are grouped into three categories based on substitution relationship type:

Direct Manufacturer Equivalents: Parts with identical electrical specifications and packaging, differing only in manufacturer or packaging format (Tube vs. Tape & Reel).

Similar Manufacturer Parts: Parts meeting all functional and electrical requirements but with variations in supply voltage range or output current specifications that remain within acceptable operating parameters.

Parametric Equivalents: Parts with identical core functionality and package type, suitable for direct replacement in circuit applications.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (Identical Specifications): SN74AC240DWR and SN74AC240DW from Texas Instruments provide direct electrical and functional equivalence to the 74AC240SC. Both maintain the 2V ~ 6V supply voltage range, 24mA output current, and identical operating temperature specifications. SN74AC240DWR is currently active in production, making it the preferred choice for new procurement. SN74AC240DW is discontinued at DiGi Electronics but may be available through alternative channels.

For Active Production Status: MC74AC240DWR2G (onsemi) and CD74AC240M96 (Texas Instruments) are both active products meeting all functional requirements. MC74AC240DWR2G maintains identical voltage and current specifications. CD74AC240M96 operates across a slightly wider supply voltage range (1.5V ~ 5.5V) while maintaining the required 24mA output current and is ROHS3 compliant with MSL 1 rating.

For Packaging Considerations: SN74AC240NSR uses a 20-SO package (0.209" width) instead of the standard 20-SOIC (0.295" width). This narrower package may require PCB layout modifications but provides identical electrical functionality and is currently active.

Avoid for New Designs: CD74AC240M (Harris Corporation) is obsolete and RoHS non-compliant, making it unsuitable for new applications requiring regulatory compliance.

Frequently Asked Questions (FAQ)

Q: Can I use SN74AC240NSR as a direct replacement for 74AC240SC? A: SN74AC240NSR is electrically equivalent but uses a narrower 20-SO package (0.209" width) compared to the standard 20-SOIC (0.295" width). PCB footprint compatibility must be verified before substitution.

Q: What is the difference between MC74AC240DWG and MC74AC240DWR2G? A: Both are onsemi products with identical electrical specifications. MC74AC240DWG is supplied in Tube packaging and is obsolete. MC74AC240DWR2G is supplied in Tape & Reel format and is currently active in production, making it the preferred choice.

Q: Is CD74AC240M96 compatible with the 74AC240SC? A: CD74AC240M96 is functionally compatible with identical output current (24mA) and operating temperature range. It operates across a wider supply voltage range (1.5V ~ 5.5V) that encompasses the 74AC240SC specification (2V ~ 6V). It is currently active and ROHS3 compliant.

Q: Why does CD74AC240M show higher output current (50mA) than other parts? A: CD74AC240M is an older Harris Corporation design with enhanced output drive capability. While this provides additional current margin, it is obsolete and RoHS non-compliant, making it unsuitable for new applications.

Q: What does MSL 1 (Unlimited) mean for moisture sensitivity? A: MSL 1 indicates unlimited shelf life without moisture bake requirements. Parts with MSL 3 (168 Hours) require moisture bake procedures if storage exceeds 168 hours in standard conditions.

Q: Are all substitute parts ROHS3 compliant? A: All recommended active and discontinued parts are ROHS3 compliant except CD74AC240M, which is RoHS non-compliant and should not be used in new designs.