SN74HC138ANS Equivalent & Substitute Parts

Part Overview

The SN74HC138ANS is a 1 x 3:8 Decoder/Demultiplexer logic integrated circuit manufactured by Texas Instruments in the 74HC series. This component functions as a decoder that converts a 3-bit binary input into one of eight mutually exclusive outputs, commonly used in address decoding and data routing applications.

The SN74HC138ANS carries a Last Time Buy product status, indicating that Texas Instruments has discontinued active production and sales of this specific part number. This status necessitates identification of equivalent substitute components that maintain identical electrical and mechanical specifications to ensure continued system functionality and design compatibility.

Substiute Parts

SN74HC138ANS

Texas InstrumentsIn Stock: 848SN74HC138ANS Datasheet

Current PartRFQ

SN74HC138ANSR

Texas InstrumentsIn Stock: 2131SN74HC138ANSR Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SN74HC138ANS is determined by strict equivalence across the following critical parameters:

Electrical Equivalence Criteria:

• Decoder/Demultiplexer type with 1 x 3:8 circuit configuration
• Output current specifications: 5.2 mA high and low
• Single supply voltage operation within 2V ~ 6V range
• Operating temperature range: -40°C ~ 85°C
• 74HC logic series classification

Mechanical Equivalence Criteria:

• 16-SOIC surface mount package with 0.209" (5.30mm) width
• 16-SO supplier device package designation

Compliance Equivalence Criteria:

• ROHS3 compliance status
• Moisture Sensitivity Level 1 (Unlimited)

The SN74HC138ANSR qualifies as a direct substitute because it maintains identical electrical specifications, mechanical packaging, and compliance certifications while offering Active product status and improved inventory availability.

Parameter Comparison

Engineering Selection Recommendations

The SN74HC138ANSR is the direct substitute for the SN74HC138ANS based on the following engineering criteria:

Electrical Compatibility: Both parts maintain identical output current specifications (5.2 mA), supply voltage range (2V ~ 6V), and operating temperature range (-40°C ~ 85°C). The 1 x 3:8 decoder/demultiplexer circuit configuration is identical, ensuring functional equivalence in all application contexts.

Mechanical Compatibility: Both components utilize the 16-SOIC surface mount package with identical physical dimensions (0.209" width, 5.30mm). PCB layout, footprint, and mounting procedures require no modification.

Compliance and Certification: Both parts maintain ROHS3 compliance and Moisture Sensitivity Level 1 (Unlimited) ratings, satisfying regulatory and environmental requirements without additional qualification.

Product Status Advantage: The SN74HC138ANSR carries Active product status with 2100 units in stock inventory, compared to the Last Time Buy status of the SN74HC138ANS with 792 units. This transition ensures long-term supply chain continuity and design longevity.

Packaging Flexibility: The SN74HC138ANSR is available in Cut Tape (CT) and Digi-Reel® packaging options, providing flexibility for both prototype and production volume requirements.

Frequently Asked Questions (FAQ)

Q: Can the SN74HC138ANSR be used as a direct replacement for the SN74HC138ANS without circuit modification?

A: Yes. The SN74HC138ANSR is electrically and mechanically identical to the SN74HC138ANS. No circuit modifications, PCB layout changes, or firmware adjustments are required. The parts are pin-compatible and functionally equivalent.

Q: What is the difference between the SN74HC138ANS and SN74HC138ANSR part numbers?

A: The suffix designations indicate packaging and product status differences. The SN74HC138ANS is designated for prototype applications with Last Time Buy status. The SN74HC138ANSR is the active production equivalent with standard commercial packaging (Cut Tape and Digi-Reel®) and Active product status.

Q: Are there any differences in the 16-SOIC package dimensions between these two parts?

A: No. Both parts use the identical 16-SOIC package with 0.209" (5.30mm) width. PCB footprints, solder pad layouts, and component placement are identical.

Q: What is the significance of the Last Time Buy status for the SN74HC138ANS?

A: Last Time Buy status indicates that Texas Instruments has ceased active production and will not accept new orders after a specified cutoff date. Existing inventory is limited. The SN74HC138ANSR with Active status ensures continued availability and supply chain reliability.

Q: Do both parts meet the same RoHS and environmental compliance standards?

A: Yes. Both the SN74HC138ANS and SN74HC138ANSR are ROHS3 compliant with Moisture Sensitivity Level 1 (Unlimited). They satisfy identical regulatory and environmental requirements.

Q: What is the operating voltage range for both parts?

A: Both parts operate with a single supply voltage range of 2V to 6V. This wide voltage range supports applications in both 3.3V and 5V logic systems.

Q: Are the output current specifications identical between the two parts?

A: Yes. Both parts provide 5.2 mA output current for both high and low logic states, ensuring identical drive capability and load-handling characteristics.