MM74HCT138MX Equivalent & Substitute Parts

Part Overview

The MM74HCT138MX is a Decoder/Demultiplexer logic integrated circuit manufactured by onsemi, configured as a 1 x 3:8 decoder in a 16-SOIC surface mount package. This component is actively produced and widely used in digital logic applications requiring address decoding and signal demultiplexing functions. The part is ROHS3 compliant with unlimited moisture sensitivity rating (MSL 1).

Substitute parts are necessary when the MM74HCT138MX becomes unavailable from primary sources, when alternative packaging formats are required for manufacturing processes, or when extended operating temperature ranges are needed for specific application environments.

Substiute Parts

MM74HCT138MX

onsemiIn Stock: 2331MM74HCT138MX Datasheet

Current PartRFQ

MC74HCT138ADR2G

onsemiIn Stock: 5167MC74HCT138ADR2G Datasheet

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CD74HCT138M96

Texas InstrumentsIn Stock: 4332CD74HCT138M96 Datasheet

DirectRFQ

74HCT138D,653

Nexperia USA Inc.In Stock: 1040774HCT138D,653 Datasheet

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SN74HCT138D

Texas InstrumentsIn Stock: 5704SN74HCT138D Datasheet

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SN74HCT138DG4

Texas InstrumentsIn Stock: 1077SN74HCT138DG4 Datasheet

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SN74HCT138DR

Texas InstrumentsIn Stock: 7462SN74HCT138DR Datasheet

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SN74HCT138DT

Texas InstrumentsIn Stock: 1503SN74HCT138DT Datasheet

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SN74HCT138NSR

Texas InstrumentsIn Stock: 3141SN74HCT138NSR Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the MM74HCT138MX is determined by the following critical parameters:

Electrical Compatibility Requirements:

• Decoder/Demultiplexer type with 1 x 3:8 circuit configuration
• Single supply voltage operation within 4.5V ~ 5.5V range
• Output current capability (4mA minimum for both high and low states)
• 74HCT logic family designation

Mechanical Compatibility Requirements:

• 16-SOIC package format with 0.154" (3.90mm) width
• Surface mount mounting type

Regulatory & Compliance Requirements:

• ROHS3 compliance
• MSL 1 (Unlimited) moisture sensitivity rating
• Active or recently discontinued product status

Parts meeting all three requirement categories are direct substitutes. Variations in operating temperature range, output current specifications above minimum thresholds, packaging format (Cut Tape vs. Tape & Reel), and manufacturer do not prevent substitution when all critical parameters align.

Parameter Comparison

Engineering Selection Recommendations

Preferred Active Substitutes (Recommended for New Designs):

MC74HCT138ADR2G and CD74HCT138M96 are the primary recommended substitutes. Both parts maintain active production status, meet all electrical and mechanical compatibility requirements, and offer extended operating temperature ranges (-55°C ~ 125°C) compared to the MM74HCT138MX. These parts are suitable for applications requiring wider temperature operation windows.

SN74HCT138DR and SN74HCT138NSR are active Texas Instruments alternatives with identical temperature specifications to the MM74HCT138MX (-40°C ~ 85°C). SN74HCT138DR matches the Cut Tape & Digi-Reel® packaging format of the original part. SN74HCT138NSR uses a wider 16-SOIC package (5.30mm width) and should only be selected when the wider package footprint is acceptable for the application.

74HCT138D,653 from Nexperia USA Inc. is an active substitute with extended upper temperature rating (-40°C ~ 125°C) and is available in Tape & Reel format.

Discontinued Parts (Not Recommended for New Designs):

SN74HCT138D, SN74HCT138DG4, and SN74HCT138DT are discontinued at DiGi Electronics and should not be selected for new production designs. These parts may only be considered for repair or maintenance of existing equipment where supply from alternative sources is confirmed.

Package Format Considerations:

Selection between Cut Tape & Digi-Reel® and Tape & Reel formats depends on manufacturing process requirements. Cut Tape format is suitable for lower-volume or manual assembly operations. Tape & Reel format is standard for automated pick-and-place assembly processes.

Frequently Asked Questions (FAQ)

Q: Can I use SN74HCT138NSR as a direct replacement for MM74HCT138MX?

A: SN74HCT138NSR is electrically compatible but uses a wider 16-SOIC package (5.30mm width) compared to the MM74HCT138MX (3.90mm width). This difference may affect PCB layout compatibility. Verify that the wider package footprint is acceptable for your application before substitution.

Q: What is the difference between Cut Tape & Digi-Reel® and Tape & Reel packaging?

A: Both formats contain the same component in 16-SOIC packages. Cut Tape & Digi-Reel® is supplied on individual tape segments suitable for manual handling or lower-volume assembly. Tape & Reel is supplied on continuous reels optimized for automated assembly equipment. Selection depends on your manufacturing process.

Q: Are discontinued parts like SN74HCT138D still usable?

A: Discontinued parts may be available from secondary distributors or inventory stock but are not recommended for new production designs. Use discontinued parts only for repair or maintenance of existing equipment where alternative sources are verified and supply continuity is confirmed.

Q: Does the extended temperature range of MC74HCT138ADR2G (-55°C ~ 125°C) affect compatibility?

A: No. Extended temperature range specifications indicate the part operates reliably across a wider temperature window. If your application operates within the original MM74HCT138MX range (-40°C ~ 85°C), the MC74HCT138ADR2G will function identically. Extended range is a superset of the original specification.

Q: What is the significance of the 4mA vs. 4.8mA output current difference?

A: The MM74HCT138MX specifies 4.8mA output current while most substitute parts specify 4mA. Both values exceed typical logic circuit requirements. Verify that your application does not depend on the higher 4.8mA specification before selecting a 4mA substitute. In most standard applications, 4mA is sufficient.

Q: Can I mix different manufacturers in the same design?

A: Yes. All listed substitutes meet identical electrical specifications, voltage supply requirements, and package standards. Mixing onsemi, Texas Instruments, and Nexperia parts in the same design is electrically compatible. Verify that your procurement and quality assurance processes support multiple manufacturer sources.