74ACT251SC Equivalent & Substitute Parts

Part Overview

The 74ACT251SC 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 74ACT251SC operates as a single-channel 8-to-1 multiplexer with output drive capabilities of 24mA for both high and low states, suitable for standard TTL logic applications requiring data selection from multiple input sources.

Substiute Parts

74ACT251SC

onsemiIn Stock: 242974ACT251SC Datasheet

Current PartRFQ

CD74AC251M

Texas InstrumentsIn Stock: 1978CD74AC251M Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the 74ACT251SC is determined by the following critical parameters that must remain compatible:

• Functional Circuit: 1 x 8:1 multiplexer configuration with identical pin functionality
• Package Type: 16-SOIC surface mount package with matching pinout
• Voltage Supply Range: Must accommodate the 4.5V ~ 5.5V operating window
• Output Drive Current: Minimum 24mA capability for both high and low states
• Mounting Compatibility: Surface mount technology on standard PCB layouts

The CD74AC251M from Texas Instruments qualifies as a substitute based on these parameters. While it offers extended specifications in certain areas, it maintains full compatibility with the core functional and physical requirements of the 74ACT251SC.

Parameter Comparison

Engineering Selection Recommendations

The CD74AC251M from Texas Instruments is a direct functional substitute for the 74ACT251SC. Both components share identical 1 x 8:1 multiplexer architecture, 16-SOIC packaging, and surface mount configuration. The CD74AC251M is listed as discontinued at DiGi Electronics, indicating limited availability similar to the obsolete status of the 74ACT251SC.

Key compliance considerations: Both parts maintain REACH Unaffected status and EAR99 export classification. The CD74AC251M carries RoHS3 compliance certification, providing additional regulatory alignment for modern manufacturing environments.

The CD74AC251M demonstrates enhanced electrical performance characteristics, including higher output drive current (75mA versus 24mA) and extended operating temperature range (-55°C ~ 125°C versus -40°C ~ 85°C). These improvements ensure compatibility with the 74ACT251SC's specified voltage supply range of 4.5V ~ 5.5V while offering superior performance margins in demanding applications.

Frequently Asked Questions (FAQ)

Q: Can the CD74AC251M directly replace the 74ACT251SC on existing PCBs?

A: Yes. Both components use identical 16-SOIC packaging with matching pinouts and surface mount footprints. No PCB redesign is required for substitution.

Q: What are the key differences between these multiplexer parts?

A: The primary differences are output drive current (CD74AC251M provides 75mA versus 24mA) and operating temperature range (CD74AC251M supports -55°C ~ 125°C versus -40°C ~ 85°C). The CD74AC251M also supports a lower minimum supply voltage of 1.5V, though both operate within the 4.5V ~ 5.5V range of the original part.

Q: Are there any voltage supply compatibility concerns?

A: No. The CD74AC251M's supply voltage range of 1.5V ~ 5.5V fully encompasses the 74ACT251SC's 4.5V ~ 5.5V requirement. Both components operate identically within this overlapping range.

Q: What is the significance of the MSL rating for these components?

A: Both parts carry MSL 1 (Unlimited) classification, indicating no moisture sensitivity restrictions during storage, handling, or assembly. This simplifies procurement and manufacturing processes.

Q: How do the compliance certifications compare?

A: Both the 74ACT251SC and CD74AC251M maintain REACH Unaffected status and EAR99 export classification. The CD74AC251M additionally carries RoHS3 compliance, providing enhanced regulatory alignment for applications requiring modern environmental standards.

Q: Is the CD74AC251M suitable for temperature-critical applications?

A: The CD74AC251M's extended operating temperature range of -55°C ~ 125°C provides greater flexibility than the 74ACT251SC's -40°C ~ 85°C range. Applications requiring operation below -40°C or above 85°C benefit from this extended specification.