SN74LS257BD Equivalent & Substitute Parts

Part Overview

The SN74LS257BD is a 4 x 2:1 multiplexer logic integrated circuit manufactured by Texas Instruments in a 16-SOIC surface mount package. This component functions as a data selector, routing one of two input signals to a single output based on control logic. The main part is currently in Last Time Buy status, indicating discontinued production. Identifying equivalent and substitute parts is necessary to maintain design continuity and ensure component availability for new production runs and field replacements.

Substiute Parts

SN74LS257BD

Texas InstrumentsIn Stock: 2602SN74LS257BD Datasheet

Current PartRFQ

SN74LS257BDR

Texas InstrumentsIn Stock: 3677SN74LS257BDR Datasheet

MFR RecommendedRFQ

SN74LS258BD

onsemiIn Stock: 40730SN74LS258BD Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the SN74LS257BD is determined by matching the following critical parameters:

• Circuit type and configuration (4 x 2:1 multiplexer)
• Output current specifications (2.6mA high, 24mA low)
• Supply voltage range (4.75V ~ 5.25V)
• Operating temperature range (0°C ~ 70°C)
• Package type (16-SOIC surface mount)
• Series classification (74LS logic family)

Parts meeting all these criteria are classified as parametric equivalents and may be used interchangeably in circuit applications. Packaging format differences (Tube vs. Tape & Reel) do not affect electrical compatibility but may impact procurement and assembly processes.

Parameter Comparison

Engineering Selection Recommendations

SN74LS257BDR (Texas Instruments, Active Status): This part is the primary recommended substitute. It matches all electrical and mechanical parameters of the SN74LS257BD and maintains active product status with ROHS3 compliance. The only difference is packaging format (Tape & Reel vs. Tube), which affects procurement and assembly logistics but not circuit performance. This part is suitable for new designs and production runs requiring RoHS compliance.

SN74LS258BD (onsemi, Obsolete Status): This part meets all electrical and mechanical parameter requirements but carries obsolete product status and RoHS non-compliance. Selection of this part should be limited to legacy system maintenance where component availability is confirmed and regulatory compliance is not a requirement.

Frequently Asked Questions (FAQ)

Q: Can SN74LS257BDR be used as a direct replacement for SN74LS257BD? A: Yes. Both parts are parametrically identical in all electrical and mechanical specifications. The difference in packaging format (Tape & Reel vs. Tube) does not affect circuit compatibility.

Q: What is the difference between Tube and Tape & Reel packaging? A: Tube packaging supplies components in plastic tubes for manual handling and small-quantity assembly. Tape & Reel packaging supplies components on continuous tape for automated pick-and-place assembly. Both formats contain identical components with identical electrical performance.

Q: Is SN74LS258BD compatible with designs using SN74LS257BD? A: SN74LS258BD meets all electrical and mechanical parameter requirements for substitution. However, its obsolete product status and RoHS non-compliance should be evaluated against project requirements and regulatory obligations before selection.

Q: What parameters must match for a part to be considered a substitute? A: Circuit configuration (4 x 2:1 multiplexer), output current ratings (2.6mA high, 24mA low), supply voltage range (4.75V ~ 5.25V), operating temperature range (0°C ~ 70°C), package type (16-SOIC), and series classification (74LS) must all match the original part.

Q: Are there inventory considerations when selecting a substitute? A: Yes. SN74LS257BDR has 3620 units in stock, SN74LS258BD has 40699 units in stock, and SN74LS257BD has 2550 units in stock. Availability should be confirmed with your supplier before final part selection.