74ACT646SC Equivalent & Substitute Parts

Part Overview

The 74ACT646SC is a non-inverting transceiver logic integrated circuit manufactured by onsemi, designed for 8-bit bidirectional data transfer with 3-state output capability. This component operates within a 4.5V to 5.5V supply voltage range and is housed in a 24-SOP package. The part is currently classified as obsolete, making identification of functionally equivalent alternatives essential for ongoing system maintenance, design updates, and procurement planning.

Substiute Parts

74ACT646SC

onsemiIn Stock: 103974ACT646SC Datasheet

Current PartRFQ

CD74ACT646M

Harris CorporationIn Stock: 1029CD74ACT646M Datasheet

SimilarRFQ

CD74ACT646M96

Texas InstrumentsIn Stock: 1001CD74ACT646M96 Datasheet

SimilarRFQ

74ACT11245DW

Texas InstrumentsIn Stock: 75274ACT11245DW Datasheet

Parametric EquivalentRFQ

MC74ACT646DWG

onsemiIn Stock: 972MC74ACT646DWG Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 74ACT646SC is determined by strict equivalence across the following critical parameters:

• Logic Type: Transceiver, Non-Inverting
• Number of Elements: 1
• Number of Bits per Element: 8
• Output Type: 3-State
• Current - Output High, Low: 24mA, 24mA
• Voltage - Supply: 4.5V ~ 5.5V
• Package / Case: 24-SOIC (0.295", 7.50mm Width)
• Mounting Type: Surface Mount

Substitute parts are grouped into two categories:

Similar Manufacturer Parts maintain identical electrical specifications and package form factor with variations in product status, compliance certifications, and packaging method.

Parametric Equivalents provide identical functional and electrical performance within the specified operating parameters, though they may originate from different base product series or manufacturers.

Parameter Comparison

Engineering Selection Recommendations

For New Designs and Active Procurement:

CD74ACT646M96 (Texas Instruments) is the preferred substitute. This part maintains full electrical and functional equivalence to the 74ACT646SC while offering active product status and ROHS3 compliance. The extended operating temperature range (-55°C to 125°C) provides additional thermal margin for demanding applications.

For Legacy System Maintenance:

CD74ACT646M (Harris Corporation) provides direct functional substitution with identical electrical specifications. This part is suitable for replacement in existing systems where RoHS compliance is not a requirement. Note that this part is also classified as obsolete.

74ACT11245DW (Texas Instruments) serves as a parametric equivalent with identical core specifications and operating temperature range matching the original 74ACT646SC. This part carries Last Time Buy status and ROHS3 compliance certification.

MC74ACT646DWG (onsemi) offers parametric equivalence from the original manufacturer. This part is ROHS3 compliant but carries a higher moisture sensitivity level (MSL 3) compared to the original specification (MSL 1), requiring controlled storage and handling conditions.

Compliance Considerations:

For applications requiring RoHS3 compliance, CD74ACT646M96, 74ACT11245DW, and MC74ACT646DWG are suitable selections. CD74ACT646M does not meet RoHS3 requirements and should be avoided in regulated applications.

Frequently Asked Questions (FAQ)

Q: Can I directly replace 74ACT646SC with CD74ACT646M96 without circuit modifications?

A: Yes. CD74ACT646M96 maintains identical electrical specifications, output drive capability (24mA), supply voltage range (4.5V to 5.5V), and 24-SOIC package form factor. No circuit modifications are required for functional substitution.

Q: What is the difference between the operating temperature ranges of these parts?

A: The 74ACT646SC, 74ACT11245DW, and MC74ACT646DWG operate from -40°C to 85°C. CD74ACT646M and CD74ACT646M96 extend this range to -55°C to 125°C, providing wider thermal operating margins. Selection depends on the specific application temperature requirements.

Q: Why does MC74ACT646DWG have a higher MSL rating than the original part?

A: MC74ACT646DWG carries MSL 3 (168 hours) versus MSL 1 (unlimited) for the original 74ACT646SC. This indicates stricter moisture control requirements during storage and handling. For applications in high-humidity environments or with extended shelf storage, the original MSL 1 specification or alternatives with MSL 1 rating are preferable.

Q: Are all substitute parts available in the same packaging format?

A: All listed substitutes use the 24-SOIC package form factor (0.295", 7.50mm width). Packaging methods differ: 74ACT646SC uses standard packaging, CD74ACT646M is supplied in tubes, and CD74ACT646M96 is supplied in tape and reel format. These differences do not affect electrical performance or PCB mounting compatibility.

Q: Which substitute should I select for a new design requiring RoHS compliance?

A: CD74ACT646M96 is the recommended choice for new designs. It combines active product status, ROHS3 compliance, extended operating temperature range, and unlimited moisture sensitivity level. This part provides the best long-term availability and regulatory compliance profile.

Q: What is the significance of "Last Time Buy" status for 74ACT11245DW?

A: Last Time Buy status indicates that the manufacturer has announced end-of-life for this part. Existing inventory may be available for purchase, but no new production is planned. For applications requiring long-term component availability, CD74ACT646M96 with active status is the more suitable choice.