74ACT646SCX Equivalent & Substitute Parts

Part Overview

The 74ACT646SCX is a non-inverting transceiver logic IC manufactured by onsemi, designed for 8-bit data bus applications 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 equivalent and substitute parts necessary for ongoing system support and new design implementations where legacy compatibility is required.

Key Parameters

Parameter	Specification
Manufacturer Part Number	74ACT646SCX
Manufacturer	onsemi
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
Operating Temperature	-40°C ~ 85°C (TA)
Package / Case	24-SOIC (0.295", 7.50mm Width)
Mounting Type	Surface Mount
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution for the 74ACT646SCX 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

Parts are classified as parametric equivalents when all electrical and mechanical parameters match exactly. Similar parts may have variations in operating temperature range, product status, or RoHS compliance but maintain functional equivalence within the specified electrical parameters.

Parameter Comparison

Part Number	Manufacturer	Logic Type	Bits per Element	Output Type	Current (mA)	Supply Voltage	Temp Range (°C)	Package	Product Status	RoHS Status
74ACT646SCX	onsemi	Transceiver, Non-Inverting	8	3-State	24, 24	4.5 ~ 5.5V	-40 ~ 85	24-SOIC	Obsolete	MSL 1
MC74ACT646DWR2G	onsemi	Transceiver, Non-Inverting	8	3-State	24, 24	4.5 ~ 5.5V	-40 ~ 85	24-SOIC	Obsolete	ROHS3, MSL 3
MC74ACT652DWR2G	onsemi	Transceiver, Non-Inverting	8	3-State	24, 24	4.5 ~ 5.5V	-40 ~ 85	24-SOIC	Obsolete	ROHS3, MSL 3
CD74ACT646M	Harris Corporation	Transceiver, Non-Inverting	8	3-State	24, 24	4.5 ~ 5.5V	-55 ~ 125	24-SOIC	Obsolete	Non-compliant
CD74ACT646M96	Texas Instruments	Transceiver, Non-Inverting	8	3-State	24, 24	4.5 ~ 5.5V	-55 ~ 125	24-SOIC	Active	ROHS3, MSL 1
74ACT11245DWR	Texas Instruments	Transceiver, Non-Inverting	8	3-State	24, 24	4.5 ~ 5.5V	-40 ~ 85	24-SOIC	Active	ROHS3, MSL 1

Engineering Selection Recommendations

MC74ACT646DWR2G and MC74ACT652DWR2G are parametric equivalents to the 74ACT646SCX, sharing identical electrical specifications and operating temperature range. Both are manufactured by onsemi and maintain the same 24-SOIC package footprint. These parts are suitable for direct replacement in applications where the original 74ACT646SCX is specified.

CD74ACT646M96 manufactured by Texas Instruments offers an extended operating temperature range (-55°C to 125°C) compared to the original part and maintains active product status. This part is ROHS3 compliant with MSL 1 rating, making it suitable for applications requiring higher temperature operation or improved long-term availability.

74ACT11245DWR, also from Texas Instruments, is an active product with ROHS3 compliance and MSL 1 rating. It provides the same electrical performance and operating temperature range as the original 74ACT646SCX while offering superior product lifecycle status.

CD74ACT646M from Harris Corporation provides functional equivalence but operates across an extended temperature range (-55°C to 125°C). This part is not RoHS compliant and should be selected only when extended temperature operation is required and RoHS compliance is not a design constraint.

Frequently Asked Questions (FAQ)

Q: Can MC74ACT646DWR2G be used as a direct replacement for 74ACT646SCX?

A: Yes. MC74ACT646DWR2G is a parametric equivalent with identical electrical specifications, output current ratings, supply voltage range, and operating temperature range. The 24-SOIC package is mechanically compatible. The primary difference is RoHS compliance status and moisture sensitivity level.

Q: What is the difference between MC74ACT646DWR2G and MC74ACT652DWR2G?

A: Both parts are parametric equivalents to the 74ACT646SCX with identical electrical and thermal specifications. The base product numbers differ (74ACT646 versus 74ACT652), but they maintain the same functional characteristics for 8-bit non-inverting transceiver applications with 3-state output.

Q: Why does CD74ACT646M96 have a different operating temperature range?

A: CD74ACT646M96 is specified for -55°C to 125°C operation, compared to the original 74ACT646SCX range of -40°C to 85°C. This extended range is a design characteristic of the Texas Instruments variant and does not affect compatibility in applications operating within the original temperature specification.

Q: Is 74ACT11245DWR suitable for new designs?

A: Yes. 74ACT11245DWR is classified as an active product with ROHS3 compliance and MSL 1 rating, making it suitable for new design implementations. It maintains electrical equivalence to the 74ACT646SCX and offers superior product lifecycle support.

Q: What packaging options are available for these substitute parts?

A: All substitute parts listed are available in 24-SOIC surface mount packages with 0.295" width (7.50mm). Packaging variations include different supplier formats: some are supplied in Tape & Reel (TR) configuration, while others may be supplied in Tube format. Verify supplier packaging specifications for procurement requirements.

Q: Are there any moisture sensitivity considerations when selecting a substitute?

A: MC74ACT646DWR2G and MC74ACT652DWR2G have MSL 3 rating (168 hours), while the original 74ACT646SCX, CD74ACT646M96, and 74ACT11245DWR have MSL 1 rating (unlimited). MSL 3 parts require controlled storage and handling conditions. Select MSL 1 parts for applications with extended shelf life or less stringent storage requirements.

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