74ACT74SCX Equivalent & Substitute Parts

Part Overview

The 74ACT74SCX is a dual D-type flip-flop logic integrated circuit manufactured by onsemi, housed in a 14-SOIC package. This component functions as a 2-element D-type flip-flop with complementary outputs, set/preset and reset capabilities, and positive edge triggering. The part is currently listed as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity.

Substiute Parts

74ACT74SCX

onsemiIn Stock: 3795374ACT74SCX Datasheet

Current PartRFQ

MC74ACT74DG

onsemiIn Stock: 2049MC74ACT74DG Datasheet

SimilarRFQ

MC74ACT74DR2G

onsemiIn Stock: 6226MC74ACT74DR2G Datasheet

Parametric EquivalentRFQ

SN74ACT74D

Texas InstrumentsIn Stock: 3013SN74ACT74D Datasheet

DirectRFQ

SN74ACT74DR

Texas InstrumentsIn Stock: 2228SN74ACT74DR Datasheet

DirectRFQ

SN74ACT74MDREP

Texas InstrumentsIn Stock: 2064SN74ACT74MDREP Datasheet

UpgradeRFQ

74AHCT74D,118

NXP SemiconductorsIn Stock: 1343174AHCT74D,118 Datasheet

SimilarRFQ

CD74ACT74M96

Texas InstrumentsIn Stock: 1786CD74ACT74M96 Datasheet

SimilarRFQ

CD74ACT74QM96G4Q1

Texas InstrumentsIn Stock: 3300CD74ACT74QM96G4Q1 Datasheet

SimilarRFQ

SN74ACT74NSR

Texas InstrumentsIn Stock: 3874SN74ACT74NSR Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 74ACT74SCX is determined by the following critical parameters:

Core Functional Parameters:

• Type: D-Type Flip-Flop with 2 elements, 1 bit per element
• Output Type: Complementary
• Trigger Type: Positive Edge
• Function: Set(Preset) and Reset capability

Electrical Performance Parameters:

• Clock Frequency: 210 MHz (minimum acceptable)
• Max Propagation Delay @ 5V, 50pF: 11 ns (maximum acceptable)
• Voltage Supply Range: 4.5V ~ 5.5V
• Current Output Capability: 24 mA minimum (High and Low)

Physical Parameters:

• Package: 14-SOIC form factor
• Mounting Type: Surface Mount

Substitute parts are grouped into three categories based on their relationship to the main part:

Parametric Equivalents: Parts with identical electrical specifications and packaging, differing only in packaging format (Tube, Tape & Reel, Cut Tape).

Direct Substitutes: Parts from alternative manufacturers (Texas Instruments, NXP) meeting or exceeding the core electrical and functional requirements within the same package family.

Similar Parts: Parts with minor deviations in non-critical parameters (clock frequency, propagation delay, quiescent current) that remain functionally compatible within the 14-SOIC package constraint.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitutes (Highest Compatibility):

MC74ACT74DG and MC74ACT74DR2G are the preferred direct replacements for 74ACT74SCX. Both are active onsemi products in the 74ACT series with identical functional specifications, clock frequency, and propagation delay. The primary advantage is improved quiescent current (4 µA vs. 20 µA), reducing power consumption. Both maintain the same operating temperature range and 14-SOIC (0.154") package footprint. MC74ACT74DG is supplied in Tube packaging, while MC74ACT74DR2G is supplied in Tape & Reel format for automated assembly.

Secondary Substitutes (Texas Instruments):

SN74ACT74DR is an active Texas Instruments product offering superior electrical performance with lower propagation delay (7.5 ns vs. 11 ns) and reduced quiescent current (2 µA). This part is suitable for applications requiring faster switching or lower power consumption. SN74ACT74D is discontinued at DiGi Electronics but remains available through alternative channels; it provides identical performance to SN74ACT74DR.

SN74ACT74MDREP extends the operating temperature range to -55°C ~ 125°C, making it suitable for industrial and automotive applications requiring wider temperature operation. This part maintains 210 MHz clock frequency and 11 ns propagation delay matching the original specification.

Extended Temperature Alternative:

CD74ACT74M96 provides extended operating temperature range (-55°C ~ 125°C) with RoHS3 compliance. Clock frequency is reduced to 85 MHz and propagation delay increases to 9.5 ns; this part is suitable only for applications where the lower performance specifications are acceptable.

Alternative Logic Family:

74AHCT74D,118 from NXP Semiconductors operates within the same voltage supply range and package footprint but uses the 74AHCT logic family. Output current is reduced to 8 mA (vs. 24 mA), and clock frequency is limited to 140 MHz. This part is suitable only for low-current applications where the reduced drive capability is acceptable.

Packaging Consideration:

SN74ACT74NSR uses a wider 14-SOIC package (0.209" vs. 0.154"). While functionally equivalent, this part requires PCB layout verification to confirm physical compatibility with existing footprints designed for the narrower 0.154" package.

Frequently Asked Questions (FAQ)

Q: Can MC74ACT74DG directly replace 74ACT74SCX without circuit modification?

A: Yes. MC74ACT74DG is a direct functional replacement with identical electrical specifications, clock frequency, propagation delay, and package footprint. The lower quiescent current (4 µA vs. 20 µA) is a performance improvement with no negative impact on circuit operation.

Q: What is the difference between MC74ACT74DG and MC74ACT74DR2G?

A: Both parts are electrically identical. The difference is packaging format: MC74ACT74DG is supplied in Tube packaging for manual assembly, while MC74ACT74DR2G is supplied in Tape & Reel format for automated pick-and-place assembly. Select based on manufacturing process requirements.

Q: Why does SN74ACT74DR have lower propagation delay than the original part?

A: SN74ACT74DR is a Texas Instruments design with optimized internal circuitry achieving 7.5 ns propagation delay compared to 11 ns for the onsemi design. Both meet the 74ACT74 functional specification. The faster performance is a benefit for timing-critical applications.

Q: Is 74AHCT74D,118 compatible with 74ACT74SCX?

A: 74AHCT74D,118 is functionally compatible but with reduced output current (8 mA vs. 24 mA). Use this part only if circuit load requirements do not exceed 8 mA per output. The 74AHCT logic family is not recommended as a primary substitute due to lower drive capability.

Q: Can I use SN74ACT74NSR as a direct replacement?

A: SN74ACT74NSR is electrically equivalent but uses a wider 14-SOIC package (0.209" vs. 0.154"). Physical compatibility with existing PCB footprints must be verified before use. If the PCB footprint accommodates the wider package, this part is functionally suitable.

Q: What is the advantage of SN74ACT74MDREP over other substitutes?

A: SN74ACT74MDREP extends the operating temperature range to -55°C ~ 125°C, making it suitable for industrial and automotive applications. It maintains the original 210 MHz clock frequency and 11 ns propagation delay. Select this part if extended temperature operation is required.

Q: Are all substitute parts RoHS3 compliant?

A: Most active substitutes (MC74ACT74DG, MC74ACT74DR2G, SN74ACT74D, SN74ACT74DR, SN74ACT74MDREP, CD74ACT74M96) are RoHS3 compliant. Verify compliance documentation for specific procurement requirements.

Q: Which substitute offers the best power efficiency?

A: SN74ACT74DR and SN74ACT74MDREP offer the lowest quiescent current at 2 µA, providing the best power efficiency. MC74ACT74DG and MC74ACT74DR2G offer 4 µA quiescent current, still significantly lower than the original 20 µA specification.