SN74LS138DRG4 Equivalent & Substitute Parts

Part Overview

The SN74LS138DRG4 is a Decoder/Demultiplexer integrated circuit manufactured by Texas Instruments, featuring a 1 x 3:8 configuration in a 16-SOIC package. This component is classified as Obsolete, which necessitates identification of active equivalent alternatives for ongoing design support and procurement continuity. The part operates under single supply voltage conditions and is suitable for surface mount applications requiring logic-level decoding and demultiplexing functions.

Substiute Parts

SN74LS138DRG4

Texas InstrumentsIn Stock: 922SN74LS138DRG4 Datasheet

Current PartRFQ

SN74LS138NSR

Texas InstrumentsIn Stock: 2865SN74LS138NSR Datasheet

MFR RecommendedRFQ

SN74LS138DR

Texas InstrumentsIn Stock: 7656SN74LS138DR Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the SN74LS138DRG4 are identified based on strict electrical and mechanical parameter equivalence. The following criteria determine substitutability:

Critical Matching Parameters:

• Decoder/Demultiplexer type with 1 x 3:8 circuit configuration
• 74LS series logic family
• Single supply voltage operation (4.75V ~ 5.25V)
• Output current specifications (400µA high, 8mA low)
• Operating temperature range (0°C ~ 70°C)
• Surface mount technology
• 16-pin SOIC package format

Acceptable Variations:

• Package width tolerance within SOIC specification (0.154" to 0.209")
• Packaging format (Tape & Reel, Cut Tape, or Digi-Reel)
• Product status transition from Obsolete to Active

All identified substitutes maintain functional and electrical equivalence while offering improved availability through Active product status.

Parameter Comparison

Engineering Selection Recommendations

SN74LS138NSR is designated as the manufacturer-recommended substitute. This part maintains full electrical equivalence and is in Active product status, ensuring long-term availability and supply chain stability. The package width variation (0.209" versus 0.154") remains within SOIC specification tolerances and does not affect functional performance. Tape & Reel packaging is suitable for automated assembly processes.

SN74LS138DR is a parametric equivalent offering identical electrical specifications and package dimensions to the original part. Active product status provides procurement reliability. Cut Tape and Digi-Reel packaging options accommodate both manual and automated assembly workflows.

Both substitutes are ROHS3 compliant and maintain the same operating parameters, making them direct functional replacements for the obsolete SN74LS138DRG4 in new designs and legacy system updates.

Frequently Asked Questions (FAQ)

Q: Can SN74LS138NSR be used as a direct replacement for SN74LS138DRG4?

A: Yes. Both parts share identical electrical specifications, circuit configuration, voltage supply requirements, and output current ratings. The package width difference (0.209" versus 0.154") is within SOIC standard tolerances and does not affect circuit performance or PCB layout compatibility.

Q: What is the difference between SN74LS138NSR and SN74LS138DR?

A: Both are electrically equivalent. The primary difference is packaging format: SN74LS138NSR is supplied in Tape & Reel format, while SN74LS138DR is available in Cut Tape and Digi-Reel formats. Package case dimensions differ slightly (0.209" versus 0.154" width), though both conform to 16-SOIC specifications.

Q: Why is the original SN74LS138DRG4 marked as Obsolete?

A: Obsolete status indicates the manufacturer has discontinued production. Active alternatives (SN74LS138NSR and SN74LS138DR) provide equivalent functionality with assured supply availability.

Q: Are there any compliance differences between the main part and substitutes?

A: No. All parts are ROHS3 compliant, REACH unaffected, and carry identical ECCN and HTSUS classifications.

Q: Which substitute should be selected for new PCB designs?

A: Either substitute is suitable. Selection depends on assembly process requirements: SN74LS138NSR for automated Tape & Reel processes, or SN74LS138DR for flexible packaging needs. Both ensure long-term component availability.