74F138SCX Equivalent & Substitute Parts

Part Overview

The 74F138SCX is a decoder/demultiplexer integrated circuit manufactured by onsemi, featuring a 1 x 3:8 configuration in a 16-SOIC package. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement. The 74F138 series decoder/demultiplexer is widely used in digital logic applications requiring address decoding and signal routing functions.

Substiute Parts

74F138SCX

onsemiIn Stock: 401174F138SCX Datasheet

Current PartRFQ

SN74F138D

Texas InstrumentsIn Stock: 3865SN74F138D Datasheet

DirectRFQ

SN74F138DR

Texas InstrumentsIn Stock: 11751SN74F138DR Datasheet

DirectRFQ

SN74F138NSR

Texas InstrumentsIn Stock: 3472SN74F138NSR Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the 74F138SCX is determined by strict electrical and mechanical compatibility across the following parameters:

• Circuit Configuration: 1 x 3:8 decoder/demultiplexer function
• Voltage Supply: 4.5V ~ 5.5V single supply operation
• Output Characteristics: 1mA high, 20mA low output current
• Operating Temperature Range: 0°C ~ 70°C
• Mounting Type: Surface mount technology
• Base Product Number: 74F138 series

Substitute parts are grouped into two categories:

Direct Substitutes (Identical Package): Parts maintaining the exact 16-SOIC (0.154", 3.90mm Width) package specification, enabling direct board-level replacement without layout modification.

Similar Substitutes (Compatible Package Variant): Parts with the same electrical specifications but utilizing the 16-SO (0.209", 5.30mm Width) package variant, requiring PCB footprint verification before implementation.

Parameter Comparison

Engineering Selection Recommendations

Primary Recommendation: SN74F138DR (Texas Instruments)

The SN74F138DR is the preferred substitute for the 74F138SCX. This part maintains identical electrical specifications and package dimensions (16-SOIC, 0.154" width), enabling direct board-level replacement. The SN74F138DR carries Active product status with ROHS3 compliance, ensuring long-term availability and regulatory alignment for new designs and production continuity.

Secondary Recommendation: SN74F138D (Texas Instruments)

The SN74F138D provides equivalent electrical and package specifications to the 74F138SCX. This part is classified as Last Time Buy, indicating limited future availability. Selection of this part should be reserved for applications where packaging format (Tube) is specifically required or where inventory constraints necessitate alternative sourcing.

Alternative Consideration: SN74F138NSR (Texas Instruments)

The SN74F138NSR maintains all electrical specifications but utilizes a 16-SO package (0.209" width) instead of the standard 16-SOIC (0.154" width). This part is suitable only when PCB footprint modification is feasible. The SN74F138NSR carries Active product status and ROHS3 compliance. Package footprint compatibility must be verified before implementation.

Frequently Asked Questions (FAQ)

Q: Can the SN74F138DR be used as a direct replacement for the 74F138SCX without PCB modification?

A: Yes. The SN74F138DR maintains identical package dimensions (16-SOIC, 0.154" width), electrical specifications, and pin configuration, enabling direct board-level substitution without layout changes.

Q: What is the difference between the SN74F138D and SN74F138DR?

A: Both parts are electrically identical with matching package specifications. The primary difference is packaging format: SN74F138D is supplied in Tube packaging, while SN74F138DR is supplied in Tape & Reel (TR) format. Selection depends on procurement and assembly requirements.

Q: Why is the SN74F138NSR listed as a similar substitute rather than a direct substitute?

A: The SN74F138NSR uses a 16-SO package (0.209" width) compared to the standard 16-SOIC (0.154" width) of the 74F138SCX. While electrically equivalent, the larger package footprint requires PCB design verification to confirm compatibility with existing board layouts.

Q: Are all substitute parts RoHS compliant?

A: Yes. All Texas Instruments substitute parts (SN74F138D, SN74F138DR, SN74F138NSR) are ROHS3 compliant. The original 74F138SCX RoHS status was not specified in available documentation.

Q: What is the product status significance for component selection?

A: Product status indicates availability trajectory. The SN74F138DR (Active) is recommended for new designs and long-term production. The SN74F138D (Last Time Buy) has limited future availability. The 74F138SCX (Obsolete) is no longer manufactured and should be replaced in active designs.

Q: Are the electrical characteristics identical across all substitute parts?

A: Yes. All substitute parts maintain identical voltage supply (4.5V ~ 5.5V), output current (1mA high, 20mA low), operating temperature (0°C ~ 70°C), and circuit configuration (1 x 3:8 decoder/demultiplexer).