CD74AC139M Equivalent & Substitute Parts

Part Overview

The CD74AC139M is a decoder/demultiplexer logic integrated circuit manufactured by Texas Instruments in the 74AC series. This device functions as a 1 x 2:4 decoder with dual independent circuits, designed for signal routing and selection applications in digital systems. The part is currently in Last Time Buy status, indicating end-of-life production. Identifying qualified substitute parts ensures design continuity and supply chain reliability for applications requiring this decoder/demultiplexer functionality.

Substiute Parts

CD74AC139M

Texas InstrumentsIn Stock: 3634CD74AC139M Datasheet

Current PartRFQ

CD74AC139M96

Harris CorporationIn Stock: 2125CD74AC139M96 Datasheet

MFR RecommendedRFQ

74AC139SC

Fairchild SemiconductorIn Stock: 981074AC139SC Datasheet

MFR RecommendedRFQ

74AC139SCX

Fairchild SemiconductorIn Stock: 3511574AC139SCX Datasheet

MFR RecommendedRFQ

MC74AC139DG

onsemiIn Stock: 1611MC74AC139DG Datasheet

MFR RecommendedRFQ

MC74AC139DR2G

onsemiIn Stock: 3782MC74AC139DR2G Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the CD74AC139M is determined by strict equivalence across the following critical parameters:

• Circuit configuration (1 x 2:4 decoder/demultiplexer)
• Independent circuits count (2)
• Output current specifications (24mA high, 24mA low)
• Package type (16-SOIC)
• Mounting type (Surface Mount)
• Base product number (74AC139)
• Supply voltage compatibility
• Operating temperature range

Substitute parts must maintain identical functional specifications and physical packaging to ensure direct replacement capability. Variations in voltage supply range, operating temperature limits, or product status are noted but do not preclude substitution when application requirements fall within the substitute part's specifications.

Parameter Comparison

Engineering Selection Recommendations

All listed substitute parts maintain functional equivalence to the CD74AC139M across the core decoder/demultiplexer specifications. Selection should prioritize product status and compliance requirements:

Active Status Parts (Recommended for New Designs):

• 74AC139SC (Fairchild Semiconductor)
• 74AC139SCX (Fairchild Semiconductor)
• MC74AC139DG (onsemi)
• MC74AC139DR2G (onsemi)

These parts carry Active product status, ensuring continued availability and manufacturing support. The onsemi variants (MC74AC139DG and MC74AC139DR2G) provide ROHS3 compliance, meeting environmental regulatory requirements. Fairchild parts (74AC139SC and 74AC139SCX) offer the highest inventory availability.

Compatibility Considerations: Applications requiring the extended operating temperature range (-55°C to 125°C) of the original CD74AC139M should verify that substitute parts with -40°C to 85°C limits meet specific thermal requirements. The CD74AC139M96 (Harris Corporation) maintains the original temperature specification but carries Obsolete status and RoHS non-compliance.

Packaging and Supply Chain: MC74AC139DR2G is supplied in Tape & Reel format, suitable for high-volume automated assembly. MC74AC139DG is supplied in Tube packaging. Fairchild variants are available in Bulk packaging. Selection should align with procurement and assembly process requirements.

Frequently Asked Questions (FAQ)

Q: Can I directly replace CD74AC139M with any of the listed substitutes?

A: Yes, all listed parts are functionally equivalent decoders/demultiplexers with identical circuit configurations (1 x 2:4), output current ratings (24mA), and 16-SOIC packaging. Direct pin-for-pin replacement is supported. Verify that your application's voltage supply and operating temperature requirements fall within the substitute part's specifications.

Q: What is the difference between MC74AC139DG and MC74AC139DR2G?

A: Both parts are manufactured by onsemi with identical electrical specifications. The primary difference is packaging: MC74AC139DG is supplied in Tube format, while MC74AC139DR2G is supplied in Tape & Reel (TR) format. Selection depends on assembly process requirements and volume.

Q: Why do some substitutes have different voltage supply ranges?

A: The original CD74AC139M supports 1.5V to 5.5V supply voltage. Fairchild and onsemi variants support 2V to 6V. Both ranges cover standard logic supply voltages (3.3V, 5V). If your application requires operation below 2V, the CD74AC139M or CD74AC139M96 must be used.

Q: Are there temperature range limitations I should consider?

A: The CD74AC139M operates from -55°C to 125°C. Fairchild and onsemi substitutes operate from -40°C to 85°C. If your application requires operation below -40°C or above 85°C, the original CD74AC139M specification must be maintained.

Q: Which substitute offers the best compliance profile?

A: MC74AC139DG and MC74AC139DR2G (onsemi) both carry ROHS3 compliance and REACH Unaffected status, meeting current environmental regulations. Fairchild parts do not specify RoHS status. The Harris CD74AC139M96 is RoHS non-compliant.

Q: What is the inventory status of these parts?

A: Current inventory levels are: 74AC139SCX (35,026 pcs), 74AC139SC (9,709 pcs), CD74AC139M96 (2,070 pcs), MC74AC139DR2G (3,677 pcs), and MC74AC139DG (1,538 pcs). Fairchild variants offer the highest availability.