74ACT251MTCX Equivalent & Substitute Parts

Part Overview

The 74ACT251MTCX is a 1 x 8:1 multiplexer logic integrated circuit manufactured by onsemi in a 16-TSSOP surface mount package. This component is classified as obsolete, making identification of functionally equivalent alternatives essential for ongoing design support and production continuity. The part operates from a single 4.5V to 5.5V supply with output drive capability of 24mA high and low, suitable for standard logic-level applications requiring 8-to-1 data selection.

Substiute Parts

74ACT251MTCX

onsemiIn Stock: 320574ACT251MTCX Datasheet

Current PartRFQ

CD74AC251M

Texas InstrumentsIn Stock: 1978CD74AC251M Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the 74ACT251MTCX is determined by the following critical parameters:

• Functional equivalence: Identical 1 x 8:1 multiplexer circuit configuration
• Logic family compatibility: 74AC series logic family
• Supply voltage range: Must accommodate the 4.5V to 5.5V operating window
• Output drive capability: Minimum 24mA output current requirement
• Package compatibility: Surface mount technology with pinout alignment
• Operating temperature range: Must support -40°C to 85°C minimum

The CD74AC251M from Texas Instruments satisfies these substitution criteria through functional equivalence in the 74AC multiplexer family, though with enhanced electrical performance characteristics and different packaging.

Parameter Comparison

Engineering Selection Recommendations

The CD74AC251M provides functional substitution for the 74ACT251MTCX with the following considerations based on provided specifications:

Electrical Performance: The CD74AC251M delivers enhanced output drive capability at 75mA compared to the 24mA specification of the 74ACT251MTCX. This increased current capacity is compatible with applications designed for the original part and provides additional margin for load driving.

Supply Voltage Compatibility: The CD74AC251M operates across a wider supply voltage range (1.5V to 5.5V) compared to the 74ACT251MTCX (4.5V to 5.5V). Applications utilizing the original 4.5V to 5.5V window remain fully compatible.

Temperature Range: The CD74AC251M supports an extended operating temperature range of -55°C to 125°C, exceeding the -40°C to 85°C specification of the 74ACT251MTCX. This provides enhanced thermal margin for demanding environments.

Package Transition: The CD74AC251M uses a 16-SOIC package versus the 16-TSSOP package of the original part. PCB layout modification is required for package substitution, though both are standard surface mount packages with equivalent pinout functionality.

Compliance Status: Both parts maintain MSL 1 (Unlimited) moisture sensitivity classification and REACH Unaffected status, ensuring equivalent handling and environmental compliance.

Frequently Asked Questions (FAQ)

Q: Can the CD74AC251M directly replace the 74ACT251MTCX without circuit modification?

A: Functional substitution is possible with PCB layout modification due to package differences. The 74ACT251MTCX uses 16-TSSOP packaging while the CD74AC251M uses 16-SOIC packaging. Pinout functionality is equivalent, but physical footprint redesign is required.

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

A: The CD74AC251M provides higher output drive current (75mA versus 24mA), wider supply voltage range (1.5V to 5.5V versus 4.5V to 5.5V), and extended operating temperature range (-55°C to 125°C versus -40°C to 85°C). All differences represent enhanced or equivalent performance for the original application window.

Q: Are there pin-to-pin compatibility considerations?

A: Both parts implement the 1 x 8:1 multiplexer function with identical logic pinout. Package differences (TSSOP versus SOIC) require footprint redesign but do not affect functional pin assignment or signal compatibility.

Q: What is the significance of the product status difference?

A: The 74ACT251MTCX is classified as obsolete, while the CD74AC251M is discontinued at DiGi Electronics. Both statuses indicate limited availability through standard distribution channels. Component sourcing from alternative suppliers or inventory channels may be necessary for either part.

Q: Are moisture sensitivity and compliance ratings equivalent?

A: Yes. Both parts maintain MSL 1 (Unlimited) classification and REACH Unaffected status, ensuring equivalent handling requirements, storage conditions, and environmental compliance for manufacturing and deployment.