74AC540SCX Equivalent & Substitute Parts

Part Overview

The 74AC540SCX is an inverting buffer logic integrated circuit manufactured by onsemi, designed for applications requiring signal inversion with 3-state output capability. This device operates across a 2V to 6V supply voltage range and is housed in a 20-SOIC surface mount package. The part is currently in active production status with ROHS3 compliance and 1641 units available in new original stock.

Substitute parts become necessary when the primary part number is unavailable, when specific packaging requirements differ, or when alternative manufacturers' versions meet the same electrical and mechanical specifications for the application.

Substiute Parts

74AC540SCX

onsemiIn Stock: 173674AC540SCX Datasheet

Current PartRFQ

MC74AC540DWR2G

onsemiIn Stock: 1654MC74AC540DWR2G Datasheet

DirectRFQ

MC74AC540DWG

onsemiIn Stock: 2151MC74AC540DWG Datasheet

SimilarRFQ

CD74AC540M

Harris CorporationIn Stock: 2961CD74AC540M Datasheet

DirectRFQ

CD74AC540M96

Texas InstrumentsIn Stock: 1297CD74AC540M96 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 74AC540SCX is determined by the following critical parameters:

Electrical Compatibility Requirements:

• Logic Type: Buffer, Inverting
• Number of Elements: 1
• Number of Bits per Element: 8
• Output Type: 3-State
• Output Current Capability: 24mA (High and Low)
• Package / Case: 20-SOIC form factor

Voltage and Temperature Considerations:

• Supply voltage range must encompass or match the 2V ~ 6V specification
• Operating temperature range must support the -40°C ~ 85°C requirement

Packaging and Compliance:

• Surface mount mounting type required
• RoHS compliance status and MSL rating affect suitability for specific manufacturing environments

Parts are grouped into two categories: Direct substitutes (identical electrical and mechanical specifications with different packaging or manufacturer variants) and Similar substitutes (same base functionality with extended or different operating parameters).

Parameter Comparison

Engineering Selection Recommendations

Direct Substitutes (Identical Electrical and Mechanical Specifications):

MC74AC540DWR2G and MC74AC540DWG are direct functional equivalents to the 74AC540SCX. Both are manufactured by onsemi with identical logic specifications, output current ratings, and 20-SOIC packaging. The primary difference is packaging format: MC74AC540DWR2G is supplied in Tape & Reel format (matching 74AC540SCX), while MC74AC540DWG is supplied in Tube format. Both maintain ROHS3 compliance and MSL 3 rating. Selection between these should be based on procurement and assembly line requirements.

Extended Operating Range Substitutes:

CD74AC540M96 (Texas Instruments) and CD74AC540M (Harris Corporation) provide extended operating temperature range (-55°C to 125°C) and lower minimum supply voltage (1.5V) compared to the 74AC540SCX. These parts are suitable for applications requiring broader environmental specifications. CD74AC540M96 is currently active and ROHS3 compliant with superior MSL 1 rating. CD74AC540M is obsolete and RoHS non-compliant, making it unsuitable for new designs requiring regulatory compliance.

Compliance Considerations:

For applications requiring ROHS3 compliance and active product support, select from 74AC540SCX, MC74AC540DWR2G, MC74AC540DWG, or CD74AC540M96. The CD74AC540M should not be used in new designs due to obsolete status and non-compliance with current environmental regulations.

Frequently Asked Questions (FAQ)

Q: Can MC74AC540DWR2G replace 74AC540SCX directly on the PCB?

A: Yes. Both parts share identical electrical specifications, output current ratings (24mA), supply voltage range (2V ~ 6V), operating temperature range (-40°C ~ 85°C), and 20-SOIC package dimensions. Pinout and functional behavior are equivalent.

Q: What is the difference between MC74AC540DWR2G and MC74AC540DWG?

A: The electrical and functional specifications are identical. The difference is packaging format: MC74AC540DWR2G is supplied in Tape & Reel (TR) format suitable for automated assembly, while MC74AC540DWG is supplied in Tube format. Selection depends on manufacturing process requirements.

Q: Can CD74AC540M96 be used instead of 74AC540SCX?

A: CD74AC540M96 is electrically compatible and provides extended operating temperature range (-55°C to 125°C) and lower minimum supply voltage (1.5V). It is suitable for applications requiring broader environmental specifications. However, the 74AC540SCX is sufficient if the standard -40°C to 85°C range meets application requirements.

Q: Why is CD74AC540M listed as obsolete?

A: CD74AC540M is no longer in active production by Harris Corporation. For new designs, use active alternatives such as CD74AC540M96 (Texas Instruments) or onsemi variants (74AC540SCX, MC74AC540DWR2G, MC74AC540DWG).

Q: What does MSL 3 (168 Hours) mean for the 74AC540SCX?

A: Moisture Sensitivity Level 3 indicates the component can be exposed to moisture for up to 168 hours before soldering. This affects storage and handling procedures in manufacturing environments with high humidity.

Q: Are all substitute parts ROHS3 compliant?

A: No. CD74AC540M is RoHS non-compliant. All other listed substitutes (74AC540SCX, MC74AC540DWR2G, MC74AC540DWG, CD74AC540M96) are ROHS3 compliant.

Q: What is the base product number for all these parts?

A: The base product number is 74AC540. All listed parts are variants of this base design with different manufacturer designations, packaging formats, and compliance certifications.