SN74ALS138ADE4 Equivalent & Substitute Parts

Part Overview

The SN74ALS138ADE4 is a Decoder/Demultiplexer logic IC manufactured by Texas Instruments, featuring a 1 x 3:8 circuit configuration in a 16-SOIC surface mount package. This component is classified as Last Time Buy, indicating limited availability and the necessity to identify equivalent alternatives for future designs and procurement planning. The part operates within a single supply voltage range of 4.5V to 5.5V and is suitable for applications requiring address decoding and demultiplexing functions in digital logic systems.

Substiute Parts

SN74ALS138ADE4

Texas InstrumentsIn Stock: 964SN74ALS138ADE4 Datasheet

Current PartRFQ

SN74ALS138ADR

Texas InstrumentsIn Stock: 1934SN74ALS138ADR Datasheet

MFR RecommendedRFQ

SN74ALS138AD

Texas InstrumentsIn Stock: 2021SN74ALS138AD Datasheet

MFR RecommendedRFQ

SN74ALS137AD

Texas InstrumentsIn Stock: 783SN74ALS137AD Datasheet

Parametric EquivalentRFQ

SN74AS138D

Texas InstrumentsIn Stock: 1175SN74AS138D Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the SN74ALS138ADE4 is determined by strict adherence to the following parameters: identical circuit configuration (1 x 3:8), matching package type (16-SOIC), compatible voltage supply range (4.5V ~ 5.5V), equivalent output current specifications (400µA, 8mA), and overlapping operating temperature range (0°C ~ 70°C). All identified substitutes maintain these electrical and mechanical specifications, ensuring functional compatibility in decoder/demultiplexer applications.

The substitute parts are categorized as follows:

MFR Recommended Substitutes: Parts with identical electrical specifications and active or current product status, offering direct replacement capability with improved availability.

Parametric Equivalents: Parts meeting all critical electrical and mechanical parameters but differing in series designation (74ALS137, 74AS138), providing functional equivalence with potential design considerations based on logic family characteristics.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitute: SN74ALS138ADR is the preferred alternative, offering identical electrical specifications to the SN74ALS138ADE4 with Active product status and improved inventory availability (1900 pcs). The Cut Tape & Digi-Reel packaging provides flexibility for both prototype and production quantities.

Secondary Substitute: SN74AS138D provides an Active product status alternative with full parametric compatibility. The 74AS logic family designation indicates potential differences in propagation delay and power consumption characteristics compared to the 74ALS family, though all critical electrical parameters remain equivalent.

Tertiary Options: SN74ALS138AD and SN74ALS137AD maintain full electrical and mechanical compatibility but carry Last Time Buy status, similar to the original part. These options are suitable only when inventory constraints necessitate immediate procurement.

All substitute parts maintain ROHS3 compliance and MSL Level 1 rating, ensuring compatibility with standard manufacturing and storage requirements.

Frequently Asked Questions (FAQ)

Q: Can SN74ALS138ADR be used as a direct replacement for SN74ALS138ADE4?

A: Yes. Both parts share identical electrical specifications, circuit configuration, package type, voltage supply range, output current ratings, and operating temperature range. The primary difference is packaging format (Cut Tape & Digi-Reel versus Tube) and product status (Active versus Last Time Buy).

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

A: Both families meet the specified electrical parameters for this application. The 74AS family typically exhibits faster propagation delays and higher power consumption compared to 74ALS. Functional compatibility is maintained across all critical parameters listed in this reference.

Q: Are all substitute parts in the same 16-SOIC package?

A: Yes. All identified substitutes utilize the 16-SOIC (0.154", 3.90mm Width) surface mount package, ensuring PCB layout and footprint compatibility without design modifications.

Q: Why is SN74ALS138ADE4 marked as Last Time Buy?

A: Last Time Buy status indicates the manufacturer has discontinued or is discontinuing production. This necessitates identifying equivalent alternatives for ongoing design support and future procurement.

Q: Do all substitute parts meet the same compliance requirements?

A: Yes. All substitute parts are ROHS3 compliant, REACH unaffected, and carry MSL Level 1 rating, matching the compliance profile of the original SN74ALS138ADE4.