74F251ASC Equivalent & Substitute Parts

Part Overview

The 74F251ASC is a 1 x 8:1 multiplexer logic IC manufactured by onsemi in a 16-SOIC surface mount package. This component is classified as obsolete, making equivalent substitute parts necessary for new designs and production continuity. The 74F251 series provides single-supply multiplexing functionality with standardized electrical characteristics across compatible manufacturers.

Substiute Parts

74F251ASC

onsemiIn Stock: 107274F251ASC Datasheet

Current PartRFQ

SN74F251BDR

Texas InstrumentsIn Stock: 2999SN74F251BDR Datasheet

DirectRFQ

SN74F251BD

Texas InstrumentsIn Stock: 2026SN74F251BD Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the 74F251ASC is determined by strict equivalence across the following parameters:

• Circuit configuration: 1 x 8:1 multiplexer
• Package type: 16-SOIC with identical physical dimensions (0.154", 3.90mm Width)
• Electrical specifications: 4.5V ~ 5.5V supply, 3mA/24mA output current, 0°C ~ 70°C operating range
• Series compatibility: 74F logic family

The substitute parts SN74F251BDR and SN74F251BD meet all these criteria. Both are manufactured by Texas Instruments and maintain identical electrical and mechanical specifications. The primary differences are product status and packaging format (Tape & Reel versus Tube).

Parameter Comparison

Engineering Selection Recommendations

For applications currently using the 74F251ASC, the SN74F251BDR is the preferred substitute due to its active product status and availability. This part is manufactured by Texas Instruments and maintains full electrical and mechanical compatibility with identical supply voltage, output current specifications, and operating temperature range.

The SN74F251BD is a secondary option with parametric equivalence but carries a Last Time Buy status, indicating limited future availability. Selection between these two Texas Instruments alternatives should be based on packaging requirements: Tape & Reel format for automated assembly processes or Tube format for manual handling and lower-volume applications.

Both substitutes are ROHS3 compliant, providing regulatory compliance advantages over the original onsemi part.

Frequently Asked Questions (FAQ)

Q: Can SN74F251BDR and SN74F251BD be used interchangeably with 74F251ASC?

A: Yes. Both parts are parametrically equivalent across all critical specifications: circuit configuration, package dimensions, voltage supply range, output current ratings, and operating temperature. Direct substitution is supported at the board level without design modifications.

Q: What is the difference between SN74F251BDR and SN74F251BD?

A: The parts are electrically identical. The primary difference is packaging format: SN74F251BDR is supplied in Tape & Reel format suitable for pick-and-place assembly, while SN74F251BD is supplied in Tube format. Product status also differs—SN74F251BDR is Active, while SN74F251BD is Last Time Buy.

Q: Are there any compliance differences between the substitute parts and the original?

A: Yes. Both Texas Instruments substitutes are ROHS3 compliant, whereas the onsemi 74F251ASC compliance status is not specified. This provides regulatory advantage for new designs and production runs.

Q: Does the 16-SOIC package dimension match exactly across all three parts?

A: Yes. All three parts use the identical 16-SOIC package with 0.154" (3.90mm) width. PCB footprints and assembly processes require no modification.

Q: Which substitute should be selected for long-term production?

A: SN74F251BDR is recommended for long-term production due to its Active product status. SN74F251BD carries Last Time Buy status, indicating that Texas Instruments will discontinue this part after existing inventory is depleted.