SN74ALS251D Equivalent & Substitute Parts

Part Overview

The SN74ALS251D is a 1 x 8:1 multiplexer logic integrated circuit manufactured by Texas Instruments in a 16-SOIC surface mount package. This component is classified as Last Time Buy, indicating limited availability for future procurement. The SN74ALS251D operates with a single supply voltage between 4.5V and 5.5V and is suitable for applications requiring high-speed data selection across eight input lines. Finding equivalent and substitute parts is necessary due to product status constraints and to ensure design flexibility for production planning and inventory management.

Substiute Parts

SN74ALS251D

Texas InstrumentsIn Stock: 1640SN74ALS251D Datasheet

Current PartRFQ

SN74ALS251DR

Texas InstrumentsIn Stock: 932SN74ALS251DR Datasheet

MFR RecommendedRFQ

SN74ALS151D

Texas InstrumentsIn Stock: 1407SN74ALS151D Datasheet

Parametric EquivalentRFQ

SN74AS151D

Texas InstrumentsIn Stock: 2579SN74AS151D Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the SN74ALS251D is determined by strict adherence to the following electrical and mechanical parameters:

• Circuit Configuration: 1 x 8:1 multiplexer topology
• Package Type: 16-SOIC surface mount package with 0.154" width (3.90mm)
• Voltage Supply Range: 4.5V ~ 5.5V single supply operation
• Output Current Specifications: 2.6mA (high), 24mA (low)
• Operating Temperature Range: 0°C ~ 70°C
• Compliance Standards: ROHS3 compliant, REACH unaffected

Substitute parts are grouped into two categories: manufacturer-recommended substitutes (packaging variants) and parametric equivalents (functional alternatives with identical electrical characteristics).

Parameter Comparison

Engineering Selection Recommendations

SN74ALS251DR is the manufacturer-recommended substitute for the SN74ALS251D. Both parts are identical in electrical and mechanical specifications, with the primary difference being packaging format: SN74ALS251DR is supplied in Tape & Reel format while SN74ALS251D is supplied in Tube format. SN74ALS251DR maintains Active product status, making it the preferred choice for new designs and ongoing production requirements.

SN74ALS151D is a parametric equivalent offering identical electrical performance and package specifications. However, this part carries Last Time Buy status, similar to the primary part, and should be selected only when SN74ALS251DR availability is constrained.

SN74AS151D is a parametric equivalent from the 74AS logic series with identical electrical and mechanical parameters. This part is classified as Obsolete and should not be selected for new designs or long-term production planning due to limited future availability.

For new designs and production planning, SN74ALS251DR is the recommended selection. For existing designs currently using SN74ALS251D, SN74ALS251DR provides direct substitution without design modification.

Frequently Asked Questions (FAQ)

Q: Can SN74ALS251DR be used as a direct replacement for SN74ALS251D?

A: Yes. Both parts are electrically and mechanically identical. The only difference is packaging format: SN74ALS251DR uses Tape & Reel packaging while SN74ALS251D uses Tube packaging. No circuit modifications are required.

Q: What is the difference between the 74ALS and 74AS logic series?

A: Both series meet identical electrical specifications for the SN74ALS251D and SN74AS151D comparison, including voltage supply, output current, and operating temperature. The series designation indicates different manufacturing process technology, but functional parameters remain equivalent.

Q: Why is SN74ALS251D classified as Last Time Buy?

A: Last Time Buy status indicates the manufacturer has announced end-of-life for this part number. Existing inventory remains available, but no new production is planned. SN74ALS251DR, with Active status, is the recommended alternative for future procurement.

Q: Are there any compliance differences between substitute parts?

A: No. All substitute parts listed maintain identical RoHS3 compliance, REACH unaffected status, and Moisture Sensitivity Level 1 (Unlimited) ratings.

Q: Can SN74ALS151D be used instead of SN74ALS251D?

A: Yes, from an electrical and mechanical standpoint. However, SN74ALS151D also carries Last Time Buy status. For long-term production planning, SN74ALS251DR is the preferred substitute due to its Active product status.

Q: Should SN74AS151D be considered for new designs?

A: No. SN74AS151D is classified as Obsolete. While it meets all electrical and mechanical parameters, its obsolete status makes it unsuitable for new designs or production planning. Use SN74ALS251DR instead.