74AC74SCX Equivalent & Substitute Parts

Part Overview

The 74AC74SCX is a dual D-type flip-flop logic integrated circuit manufactured by onsemi in 14-SOIC surface mount packaging. 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

74AC74SCX

onsemiIn Stock: 6547874AC74SCX Datasheet

Current PartRFQ

MC74AC74DG

onsemiIn Stock: 2540MC74AC74DG Datasheet

SimilarRFQ

MC74AC74DR2G

onsemiIn Stock: 2964MC74AC74DR2G Datasheet

Parametric EquivalentRFQ

SN74AC74D

Texas InstrumentsIn Stock: 1999SN74AC74D Datasheet

DirectRFQ

SN74AC74DR

Texas InstrumentsIn Stock: 5241SN74AC74DR Datasheet

DirectRFQ

SN74AC74MDREP

Texas InstrumentsIn Stock: 3394SN74AC74MDREP Datasheet

UpgradeRFQ

74AC11074D

Texas InstrumentsIn Stock: 98174AC11074D Datasheet

SimilarRFQ

74AHC74D,118

Nexperia USA Inc.In Stock: 471574AHC74D,118 Datasheet

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CD74AC74M96

Texas InstrumentsIn Stock: 6333CD74AC74M96 Datasheet

SimilarRFQ

SN74AC74NSR

Texas InstrumentsIn Stock: 3440SN74AC74NSR Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 74AC74SCX 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: 160 MHz minimum
• Max Propagation Delay @ 5V, 50pF: 10ns maximum
• Voltage Supply Range: 2V ~ 6V
• Current Output Capability: 24mA minimum (High and Low)

Physical Parameters:

• Package: 14-SOIC (0.154", 3.90mm Width)
• Mounting Type: Surface Mount

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

Parametric Equivalents maintain all critical electrical and functional parameters within specified tolerances, differing only in packaging format or quiescent current characteristics.

Direct Equivalents from alternative manufacturers (Texas Instruments) provide identical functional performance with potentially improved specifications (lower propagation delay, reduced quiescent current).

Similar Parts share the same base functionality and package but may have minor variations in clock frequency, propagation delay, or supply voltage range that remain within acceptable design margins for most applications.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitutes (Highest Compatibility):

MC74AC74DG and MC74AC74DR2G from onsemi are the preferred direct replacements. Both maintain identical functional specifications and package dimensions to the 74AC74SCX while offering improved quiescent current performance (4 µA vs. 20 µA). Both parts are currently in active production status with ROHS3 compliance.

Secondary Substitutes (Texas Instruments):

SN74AC74DR is the recommended Texas Instruments equivalent. This part is currently active and provides superior electrical performance with 6ns propagation delay (versus 10ns) and 2 µA quiescent current. It maintains full compatibility with the 74AC74SCX in all critical parameters and is ROHS3 compliant.

SN74AC74MDREP offers extended operating temperature range (-55°C ~ 125°C) compared to the base 74AC74SCX (-40°C ~ 85°C), making it suitable for applications requiring military or industrial temperature specifications while maintaining all other electrical parameters.

Alternative Substitutes (Functional Compatibility with Limitations):

74AC11074D from Texas Instruments is available but carries Last Time Buy status. This part operates at 150 MHz (versus 160 MHz) and has a narrower supply voltage range (3V ~ 5.5V versus 2V ~ 6V). Use only when the reduced clock frequency and voltage range are acceptable for the application.

74AHC74D,118 from Nexperia is an active alternative from the 74AHC series. This part operates at 115 MHz and provides only 8mA output current (versus 24mA), making it suitable for lower-speed, lower-current applications. It offers extended temperature range (-40°C ~ 125°C) and is ROHS3 compliant.

CD74AC74M96 from Texas Instruments supports extended supply voltage range (1.5V ~ 5.5V) and temperature range (-55°C ~ 125°C) but operates at reduced clock frequency (100 MHz). This part is suitable for low-voltage or wide-temperature applications where the reduced speed is acceptable.

SN74AC74NSR is functionally equivalent to the 74AC74SCX but uses a wider 14-SOIC package (0.209" versus 0.154"). This part is suitable only if PCB layout can accommodate the larger package footprint.

Compliance and Certification:

All recommended substitutes are ROHS3 compliant and REACH unaffected. All parts maintain EAR99 export classification and identical HTSUS coding (8542.39.0001) to the original 74AC74SCX.

Frequently Asked Questions (FAQ)

Q: Can I use MC74AC74DG as a direct replacement for 74AC74SCX?

A: Yes. MC74AC74DG is a direct replacement. Both parts share identical functional specifications, clock frequency (160 MHz), propagation delay (10ns @ 5V, 50pF), output current (24mA), supply voltage range (2V ~ 6V), and 14-SOIC package dimensions (0.154", 3.90mm). MC74AC74DG is currently in active production, whereas 74AC74SCX is obsolete.

Q: What is the difference between SN74AC74DR and SN74AC74MDREP?

A: Both are Texas Instruments 74AC parts with identical clock frequency (160 MHz) and output current (24mA). The primary difference is operating temperature range: SN74AC74DR operates -40°C ~ 85°C, while SN74AC74MDREP extends to -55°C ~ 125°C. SN74AC74MDREP is suitable for military and industrial applications requiring wider temperature specifications. Both are currently active products.

Q: Why does 74AHC74D,118 show lower output current (8mA vs. 24mA)?

A: 74AHC74D,118 is from the 74AHC logic family, which is a different series than the 74AC. The 74AHC series is designed for lower power consumption and lower output drive capability. This part is suitable only for applications where 8mA output current is sufficient. The 74AC series (MC74AC74DG, SN74AC74DR) maintains the full 24mA output current of the original 74AC74SCX.

Q: Can I use SN74AC74NSR in place of 74AC74SCX?

A: SN74AC74NSR is functionally equivalent but uses a different package footprint. The 14-SOIC package is wider (0.209" versus 0.154"), which may not fit existing PCB layouts designed for the original 74AC74SCX. Use this part only if your PCB design can accommodate the larger package dimensions.

Q: Is CD74AC74M96 suitable for my 160 MHz application?

A: No. CD74AC74M96 operates at only 100 MHz maximum clock frequency, which is below the 160 MHz specification of the 74AC74SCX. This part is suitable only for applications requiring 100 MHz or lower clock speeds. For 160 MHz operation, use MC74AC74DG, SN74AC74DR, or SN74AC74MDREP.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All substitute parts listed are ROHS3 compliant and REACH unaffected, matching the compliance status of the original 74AC74SCX.

Q: Which substitute offers the best performance improvement?

A: SN74AC74DR from Texas Instruments provides the best performance improvement with 6ns propagation delay (versus 10ns in the original) and 2 µA quiescent current (versus 20 µA). This part is currently in active production and maintains all other electrical specifications of the 74AC74SCX.