SN74ALS138ADR Equivalent & Substitute Parts

Part Overview

The SN74ALS138ADR is a decoder/demultiplexer integrated circuit manufactured by Texas Instruments, designed for 1 x 3:8 logic decoding applications. This device is classified as a Logic component in the 74ALS series and is currently in active product status. The SN74ALS138ADR is packaged in a 16-SOIC surface mount configuration with a 0.154" (3.90mm) width specification.

Finding equivalent and substitute parts may be necessary due to inventory constraints, supply chain considerations, or specific application requirements where alternative logic decoder variants meet the same functional and electrical specifications.

Substiute Parts

SN74ALS138ADR

Texas InstrumentsIn Stock: 1934SN74ALS138ADR Datasheet

Current PartRFQ

SN74AS138DR

Texas InstrumentsIn Stock: 2024SN74AS138DR Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the SN74ALS138ADR are identified based on strict parametric equivalence across the following critical specifications:

• Circuit configuration: 1 x 3:8 decoder/demultiplexer topology
• Package type: 16-SOIC surface mount with 0.154" (3.90mm) width
• Voltage supply range: 4.5V ~ 5.5V single supply operation
• Output current specifications: 400µA high, 8mA low
• Operating temperature range: 0°C ~ 70°C
• Compliance certifications: ROHS3, REACH Unaffected, EAR99

Substitute parts must maintain identical electrical performance characteristics and physical package dimensions to ensure direct functional replacement without circuit redesign.

Parameter Comparison

Engineering Selection Recommendations

The SN74ALS138ADR is the primary selection for new designs and applications requiring active product status with ongoing manufacturer support. This part maintains full compliance with ROHS3 and REACH requirements and is available in production quantities.

The SN74AS138DR serves as a parametric equivalent substitute where identical electrical and mechanical specifications are required. However, this part is discontinued at DiGi Electronics, limiting its availability for new procurement. Selection of the SN74AS138DR should be restricted to legacy system maintenance or applications where existing inventory is available through alternative distribution channels.

Both parts satisfy identical functional requirements, voltage specifications, current ratings, temperature operating ranges, and package dimensions. The choice between these parts should be determined by inventory availability and product lifecycle status rather than electrical performance differences.

Frequently Asked Questions (FAQ)

Q: Can the SN74AS138DR directly replace the SN74ALS138ADR in existing circuits?

A: Yes. Both parts share identical circuit configuration (1 x 3:8), package type (16-SOIC), voltage supply range (4.5V ~ 5.5V), output current specifications (400µA, 8mA), and operating temperature range (0°C ~ 70°C). Direct substitution is electrically and mechanically compatible without circuit modification.

Q: What is the primary difference between these substitute parts?

A: The SN74ALS138ADR belongs to the 74ALS logic family, while the SN74AS138DR belongs to the 74AS logic family. Both families operate within identical electrical parameters for this decoder/demultiplexer configuration. The primary distinction is product status: the SN74ALS138ADR is active, while the SN74AS138DR is discontinued at DiGi Electronics.

Q: Are both parts RoHS compliant?

A: Yes. Both the SN74ALS138ADR and SN74AS138DR are ROHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements.

Q: What package considerations apply to these parts?

A: Both parts are supplied in 16-SOIC surface mount packages with identical 0.154" (3.90mm) width specifications. Pin configuration and PCB footprint requirements are identical, ensuring direct board-level compatibility.

Q: Should I use the SN74AS138DR for new designs?

A: No. For new designs, the SN74ALS138ADR is recommended due to its active product status and ongoing availability. The SN74AS138DR should be considered only for legacy system support where existing inventory exists.