CD74AC540ME4 Equivalent & Substitute Parts

Part Overview

The CD74AC540ME4 is a Buffer, Inverting logic IC manufactured by Texas Instruments, featuring 1 element with 8 bits per element and 3-state output capability in a 20-SOIC package. This part is discontinued at DiGi Electronics, making equivalent substitute parts necessary for ongoing design requirements and production continuity. The 74AC540 series provides standardized inverting buffer functionality across multiple manufacturers, enabling direct substitution based on electrical and mechanical compatibility.

Substiute Parts

CD74AC540ME4

Texas InstrumentsIn Stock: 1118CD74AC540ME4 Datasheet

Current PartRFQ

CD74AC540M

Harris CorporationIn Stock: 2961CD74AC540M Datasheet

MFR RecommendedRFQ

74AC540SCX

onsemiIn Stock: 173674AC540SCX Datasheet

MFR RecommendedRFQ

MC74AC540DWG

onsemiIn Stock: 2151MC74AC540DWG Datasheet

MFR RecommendedRFQ

MC74AC540DWR2G

onsemiIn Stock: 1654MC74AC540DWR2G Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the CD74AC540ME4 is determined by the following critical parameters: logic type (Buffer, Inverting), element and bit configuration (1 element, 8 bits per element), output type (3-State), output current capability (24mA, 24mA), package type (20-SOIC), and mounting method (Surface Mount). All substitute parts must maintain the 74AC540 base product number designation and identical package dimensions.

The substitute parts are grouped into two categories based on electrical operating ranges:

Category 1 - Extended Temperature Range (CD74AC540M): Maintains the original supply voltage range of 1.5V ~ 5.5V with operating temperature of -55°C ~ 125°C. This part is obsolete and non-compliant with RoHS standards.

Category 2 - Standard Operating Range (74AC540SCX, MC74AC540DWG, MC74AC540DWR2G): Operates within 2V ~ 6V supply voltage range with -40°C ~ 85°C operating temperature. All three parts are active, RoHS3 compliant, and available from onsemi. These parts differ only in packaging format (Tape & Reel or Tube) and moisture sensitivity level (MSL 3, 168 Hours).

Parameter Comparison

Engineering Selection Recommendations

For applications requiring the CD74AC540ME4, the following selection criteria apply:

Primary Substitutes (Recommended): The onsemi parts 74AC540SCX, MC74AC540DWG, and MC74AC540DWR2G are active products with ROHS3 compliance and current manufacturing status. These parts are functionally equivalent within the 2V ~ 6V supply voltage range and -40°C ~ 85°C operating temperature. Selection between these three parts depends on packaging requirements: 74AC540SCX and MC74AC540DWR2G are supplied in Tape & Reel format suitable for automated assembly, while MC74AC540DWG is supplied in Tube format for manual handling.

Secondary Substitute (Limited Use): The CD74AC540M from Harris Corporation maintains the extended supply voltage range (1.5V ~ 5.5V) and temperature range (-55°C ~ 125°C) of the original part. However, this part is obsolete and non-compliant with RoHS standards, making it unsuitable for new designs or applications with environmental compliance requirements.

Compliance Consideration: Applications requiring RoHS3 compliance must use the onsemi substitutes (74AC540SCX, MC74AC540DWG, MC74AC540DWR2G). The CD74AC540M does not meet this requirement.

Frequently Asked Questions (FAQ)

Q: Can the onsemi 74AC540SCX, MC74AC540DWG, and MC74AC540DWR2G be used interchangeably with the CD74AC540ME4?

A: These parts are functionally equivalent within their specified operating ranges. The primary difference is the supply voltage range: onsemi parts operate at 2V ~ 6V versus the original 1.5V ~ 5.5V. If your application operates within 2V ~ 6V and -40°C ~ 85°C, these substitutes are compatible. The three onsemi variants differ only in packaging format and moisture sensitivity level, not electrical function.

Q: What is the difference between 74AC540SCX, MC74AC540DWG, and MC74AC540DWR2G?

A: All three parts are electrically identical. The differences are: 74AC540SCX and MC74AC540DWR2G are supplied in Tape & Reel format with MSL 3 (168 Hours) moisture sensitivity; MC74AC540DWG is supplied in Tube format with MSL 3 (168 Hours) moisture sensitivity. Selection depends on assembly process requirements and handling procedures.

Q: Is the CD74AC540M a suitable substitute?

A: The CD74AC540M is electrically compatible and maintains the extended operating ranges of the original part. However, it is obsolete and RoHS non-compliant. Use only if your application has specific requirements for the 1.5V ~ 5.5V supply range and -55°C ~ 125°C temperature range, and environmental compliance is not required.

Q: What are the key parameters that determine substitution compatibility?

A: Substitution is determined by: logic type (Buffer, Inverting), element configuration (1 element, 8 bits per element), output type (3-State), output current (24mA, 24mA), package type (20-SOIC), and mounting method (Surface Mount). All substitute parts must maintain these specifications. Operating voltage and temperature ranges may vary between substitutes.

Q: Are there any moisture sensitivity considerations for the onsemi substitutes?

A: The onsemi parts (74AC540SCX, MC74AC540DWG, MC74AC540DWR2G) have MSL 3 rating with 168-hour floor life. This requires controlled storage conditions and handling procedures during assembly. The original CD74AC540ME4 has MSL 1 (Unlimited), indicating no moisture sensitivity restrictions.