SN74F138NS Equivalent & Substitute Parts

Part Overview

The SN74F138NS is a Decoder/Demultiplexer logic integrated circuit manufactured by Texas Instruments, featuring a 1 x 3:8 configuration in a 16-SOIC surface mount package. This component is classified as Last Time Buy, indicating limited availability from the original packaging format. The identification of equivalent substitute parts is necessary to ensure design continuity and procurement flexibility, particularly given the product's end-of-life status in its original tube packaging configuration.

Substiute Parts

SN74F138NS

Texas InstrumentsIn Stock: 1822SN74F138NS Datasheet

Current PartRFQ

SN74F138NSR

Texas InstrumentsIn Stock: 3472SN74F138NSR Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SN74F138NS is based on strict equivalence across the following critical parameters:

• Functional Circuit: Identical 1 x 3:8 Decoder/Demultiplexer configuration
• Electrical Specifications: Matching voltage supply range (4.5V ~ 5.5V), output current ratings (1mA high, 20mA low), and operating temperature range (0°C ~ 70°C)
• Package Compatibility: Identical 16-SOIC surface mount package with matching pinout and mechanical dimensions
• Compliance Standards: ROHS3 compliance and MSL Level 1 rating maintained across all substitutes
• Manufacturer Consistency: Same manufacturer (Texas Instruments) ensures design validation and quality standards

The SN74F138NSR qualifies as a direct substitute based on these parameters. The primary distinction is packaging format: the original part is supplied in tube packaging (Last Time Buy status), while the substitute is supplied in Tape & Reel format with Active product status.

Parameter Comparison

Engineering Selection Recommendations

The SN74F138NSR is the direct equivalent substitute for the SN74F138NS. Selection between these parts should be based on the following factors:

SN74F138NS (Original): Appropriate for existing inventory management or applications where tube packaging is specified. Product status is Last Time Buy, indicating limited future availability.

SN74F138NSR (Substitute): Recommended for new designs and ongoing procurement. This part maintains identical electrical and mechanical specifications while offering Active product status and greater availability through Tape & Reel packaging. Both parts carry equivalent compliance certifications (ROHS3, REACH Unaffected) and identical moisture sensitivity ratings.

The transition from tube to Tape & Reel packaging does not affect circuit performance, electrical characteristics, or board-level compatibility. Both parts are suitable for automated assembly processes and manual placement applications.

Frequently Asked Questions (FAQ)

Q: Are the SN74F138NS and SN74F138NSR electrically identical?

A: Yes. Both parts share identical electrical specifications including voltage supply range (4.5V ~ 5.5V), output current ratings (1mA high, 20mA low), operating temperature range (0°C ~ 70°C), and circuit configuration (1 x 3:8 Decoder/Demultiplexer).

Q: What is the difference between these two parts?

A: The primary difference is packaging format and product status. The SN74F138NS is supplied in tube packaging with Last Time Buy status. The SN74F138NSR is supplied in Tape & Reel format with Active product status, indicating ongoing availability and manufacturing support.

Q: Can I use SN74F138NSR as a direct replacement for SN74F138NS on a PCB?

A: Yes. Both parts use the identical 16-SOIC surface mount package with matching pinout and mechanical dimensions. No circuit modifications or board redesign is required.

Q: Are there any compliance or certification differences?

A: No. Both parts maintain identical compliance status: ROHS3 Compliant, REACH Unaffected, and Moisture Sensitivity Level 1 (Unlimited).

Q: Which part should I specify for new designs?

A: The SN74F138NSR is recommended for new designs due to its Active product status and greater long-term availability. The SN74F138NS should be reserved for applications requiring existing inventory or where tube packaging is specifically mandated.

Q: Are there any temperature or voltage operating differences?

A: No. Both parts operate identically across the full temperature range (0°C ~ 70°C) and voltage supply range (4.5V ~ 5.5V).