74ACT251SCX Equivalent & Substitute Parts

Part Overview

The 74ACT251SCX is a 1 x 8:1 multiplexer logic integrated circuit manufactured by onsemi in a 16-SOIC surface mount package. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement. The 74ACT251 series provides single-supply multiplexing functionality suitable for digital logic applications requiring channel selection from eight input lines.

Substiute Parts

74ACT251SCX

onsemiIn Stock: 243074ACT251SCX Datasheet

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CD74AC251M

Texas InstrumentsIn Stock: 1978CD74AC251M Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution for the 74ACT251SCX is determined by the following critical parameters:

• Functional equivalence: Identical 1 x 8:1 multiplexer circuit configuration
• Package compatibility: 16-SOIC surface mount package with matching 0.154" (3.90mm) width
• Electrical interface: Single supply voltage operation with compatible logic levels
• Output drive capability: Sufficient current sourcing and sinking for downstream logic
• Environmental compliance: REACH and RoHS status for regulatory requirements

The CD74AC251M from Texas Instruments qualifies as a substitute based on matching circuit topology, identical package form factor, and compatible single-supply operation. Both parts belong to the 74AC logic family and share the same base product number designation (74AC251).

Parameter Comparison

Engineering Selection Recommendations

The CD74AC251M is a direct functional substitute for the 74ACT251SCX. Both components are REACH compliant and carry identical export classification (EAR99). The CD74AC251M offers extended operating temperature range (-55°C to 125°C versus -40°C to 85°C) and higher output drive current (75mA versus 24mA), providing enhanced performance margins in most applications. The CD74AC251M supports a wider supply voltage range (1.5V to 5.5V), enabling operation in lower-voltage systems while maintaining compatibility with standard 5V logic levels.

Selection between these parts should be based on supply voltage requirements, operating temperature constraints, and output current demands of the specific application circuit.

Frequently Asked Questions (FAQ)

Q: Can the CD74AC251M replace the 74ACT251SCX in existing designs?

A: Yes. Both parts share identical 1 x 8:1 multiplexer functionality, 16-SOIC package geometry, and single-supply operation. Direct substitution is possible at the component level without PCB modifications.

Q: What are the key differences between these parts?

A: The CD74AC251M provides higher output drive current (75mA versus 24mA), extended operating temperature range (-55°C to 125°C versus -40°C to 85°C), and wider supply voltage tolerance (1.5V to 5.5V versus 4.5V to 5.5V). These differences represent performance enhancements rather than functional incompatibilities.

Q: Are there package compatibility concerns?

A: No. Both parts use identical 16-SOIC surface mount packaging with 0.154" (3.90mm) width. PCB footprints and reflow soldering profiles are directly compatible.

Q: What is the significance of the obsolete status for the 74ACT251SCX?

A: Obsolete status indicates the part is no longer manufactured by onsemi. The CD74AC251M from Texas Instruments provides continued availability for the 1 x 8:1 multiplexer function in the 74AC logic family.

Q: Are both parts RoHS and REACH compliant?

A: Both parts are REACH compliant. The CD74AC251M carries RoHS3 compliance certification. Compliance documentation should be verified against specific project requirements.