SN74AHCT138MDREP Equivalent & Substitute Parts

Part Overview

The SN74AHCT138MDREP is a decoder/demultiplexer logic integrated circuit manufactured by Texas Instruments. This 1 x 3:8 decoder operates as a single-supply device with 16-SOIC surface mount packaging. The part is currently in active production status with 871 units available in new original inventory. Substitute parts are identified when equivalent functional performance, electrical specifications, and mechanical compatibility can be maintained across alternative manufacturers while preserving circuit reliability and system integration requirements.

Substiute Parts

SN74AHCT138MDREP

Texas InstrumentsIn Stock: 945SN74AHCT138MDREP Datasheet

Current PartRFQ

74AHCT138S16-13

Diodes IncorporatedIn Stock: 125374AHCT138S16-13 Datasheet

MFR RecommendedRFQ

MC74VHCT138ADR2G

onsemiIn Stock: 65901MC74VHCT138ADR2G Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the SN74AHCT138MDREP are qualified based on the following criteria:

Functional Equivalence: All substitute parts maintain identical decoder/demultiplexer architecture with 1 x 3:8 circuit configuration and single independent circuit.

Electrical Compatibility: Output current specifications (8mA high, 8mA low), single-supply voltage range (4.5V ~ 5.5V), and logic family compatibility ensure direct functional replacement.

Thermal Performance: Operating temperature ranges must support the application requirements. The main part specifies -55°C ~ 125°C; substitute parts with -40°C ~ 125°C or -55°C ~ 125°C are acceptable depending on system thermal requirements.

Mechanical Compatibility: All substitutes use identical 16-SOIC surface mount packaging (0.154", 3.90mm width), ensuring PCB footprint and assembly process compatibility.

Regulatory Compliance: All parts maintain ROHS3 compliance, MSL Level 1 rating, and REACH unaffected status, preserving supply chain and environmental requirements.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitute - 74AHCT138S16-13 (Diodes Incorporated): This part is manufacturer-recommended and maintains full electrical and mechanical compatibility with the SN74AHCT138MDREP. The operating temperature range of -40°C ~ 125°C is suitable for standard industrial applications. All regulatory certifications (ROHS3, MSL Level 1) are equivalent. Inventory availability of 1149 units supports production requirements.

Parametric Equivalent - MC74VHCT138ADR2G (onsemi): This part provides parametric equivalence with identical electrical specifications and operating temperature range (-55°C ~ 125°C). The 74VHCT series maintains functional compatibility with 74AHCT logic families. Significantly higher inventory availability (65832 units) supports extended production schedules. All compliance certifications are maintained.

Temperature Consideration: Applications requiring extended low-temperature operation below -40°C should prioritize the SN74AHCT138MDREP or MC74VHCT138ADR2G, both rated to -55°C. The 74AHCT138S16-13 is suitable for applications with minimum operating temperature of -40°C or higher.

Frequently Asked Questions (FAQ)

Q: Can the 74AHCT138S16-13 directly replace the SN74AHCT138MDREP on existing PCBs?

A: Yes. Both parts use identical 16-SOIC surface mount packaging with matching pinouts and electrical specifications. No PCB modifications are required. The primary difference is the operating temperature minimum of -40°C versus -55°C.

Q: What is the difference between the 74AHCT and 74VHCT series?

A: Both series are compatible decoder/demultiplexer logic families with identical functional performance, output current ratings, and voltage supply specifications. The MC74VHCT138ADR2G (74VHCT series) is manufactured by onsemi and provides equivalent performance to the 74AHCT series parts.

Q: Are all three parts RoHS compliant?

A: Yes. All three parts—SN74AHCT138MDREP, 74AHCT138S16-13, and MC74VHCT138ADR2G—are ROHS3 compliant with MSL Level 1 moisture sensitivity rating and REACH unaffected status.

Q: Which substitute part has the best inventory availability?

A: The MC74VHCT138ADR2G from onsemi has the highest inventory availability at 65832 units, compared to 1149 units for the 74AHCT138S16-13 and 871 units for the original SN74AHCT138MDREP.

Q: Can I use the 74AHCT138S16-13 in applications requiring -55°C operation?

A: No. The 74AHCT138S16-13 is rated to -40°C minimum. For applications requiring -55°C operation, use the SN74AHCT138MDREP or MC74VHCT138ADR2G.

Q: Are the output current specifications identical across all three parts?

A: Yes. All three parts provide 8mA output current for both high and low states, ensuring equivalent drive capability and logic level compatibility.