MM74HC74ASJX Equivalent & Substitute Parts

Part Overview

The MM74HC74ASJX is a dual D-type flip-flop logic integrated circuit manufactured by onsemi in the 74HC series. This device features two independent D-type flip-flops with Set (Preset) and Reset functions, complementary outputs, and positive edge triggering. The part is classified as Obsolete, making equivalent substitute parts necessary for ongoing design support and procurement.

Key Parameters

Parameter	Value
Base Product Number	74HC74
Type	D-Type Flip-Flop
Number of Elements	2
Number of Bits per Element	1
Output Type	Complementary
Function	Set (Preset) and Reset
Trigger Type	Positive Edge
Voltage Supply Range	2V to 6V
Operating Temperature Range	-40°C to 85°C
Package Type	14-SOIC (0.209", 5.30mm Width)
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution of the MM74HC74ASJX is determined by strict equivalence across the following critical parameters:

Base product number: 74HC74
Functional architecture: Dual D-type flip-flop with Set/Reset capability
Output configuration: Complementary outputs
Trigger mechanism: Positive edge triggered
Supply voltage range: 2V to 6V
Package type: 14-SOIC surface mount
Mounting type: Surface mount

Substitute parts must maintain identical functional behavior, pin compatibility, and electrical operating ranges. Variations in propagation delay, quiescent current, clock frequency, and input capacitance are permitted within the 74HC74 logic family specification, as these parameters do not affect functional interchangeability in standard applications.

Parameter Comparison

Part Number	Manufacturer	Status	Clock Frequency (MHz)	Max Propagation Delay @ 6V, 50pF (ns)	Quiescent Current (µA)	Output Current High/Low (mA)	Input Capacitance (pF)	Operating Temp (°C)	Package
MM74HC74ASJX	onsemi	Obsolete	94	19	4	5.2 / 5.2	5	-40 to 85	14-SOIC (0.209", 5.30mm)
MM74HC74AMX	Fairchild Semiconductor	Active	94	19	4	5.2 / 5.2	5	-40 to 85	14-SOIC (0.154", 3.90mm)
74HC74D	Toshiba Semiconductor and Storage	Active	67	26	2	5.2 / 5.2	5	-40 to 85	14-SOIC (0.154", 3.90mm)
74HC74D,653	NXP Semiconductors	Active	82	37	40	5.2 / 5.2	4.6	-40 to 125	14-SOIC (0.154", 3.90mm)
74HC74D/AUJ	NXP USA Inc.	Active	82	37	40	5.2 / 5.2	4.6	-40 to 125	14-SOIC (0.154", 3.90mm)
CD74HC74M	Texas Instruments	Discontinued at DiGi Electronics	50	30	4	5.2 / 5.2	10	-55 to 125	14-SOIC (0.154", 3.90mm)
CD74HC74M96	Texas Instruments	Active	50	30	4	5.2 / 5.2	10	-55 to 125	14-SOIC (0.154", 3.90mm)
CD74HC74MT	Texas Instruments	Obsolete	50	30	4	5.2 / 5.2	10	-55 to 125	14-SOIC (0.154", 3.90mm)
SN74HC74DG4	Texas Instruments	Discontinued at DiGi Electronics	60	30	4	5.2 / 5.2	3	-40 to 85	14-SOIC (0.154", 3.90mm)
SN74HC74DR	Texas Instruments	Active	60	15	4	5.2 / 5.2	3	-40 to 85	14-SOIC (0.154", 3.90mm)
SN74HC74DRG4	Texas Instruments	Discontinued at DiGi Electronics	60	30	4	5.2 / 5.2	3	-40 to 85	14-SOIC (0.154", 3.90mm)

Engineering Selection Recommendations

For direct replacement of the obsolete MM74HC74ASJX, select from active product status parts to ensure long-term availability and supply chain continuity. The MM74HC74AMX from Fairchild Semiconductor provides the closest electrical match with identical clock frequency (94 MHz) and propagation delay (19 ns), though it uses a narrower 14-SOIC package (0.154" vs. 0.209" width).

The SN74HC74DR from Texas Instruments offers superior propagation delay performance (15 ns) with active product status and full RoHS3 compliance. This part is suitable for applications requiring faster switching characteristics while maintaining the same supply voltage range and operating temperature window.

For applications requiring extended temperature operation beyond 85°C, the 74HC74D,653 from NXP Semiconductors and CD74HC74M96 from Texas Instruments extend the upper operating limit to 125°C. The NXP variant maintains the standard -40°C lower limit, while the Texas Instruments option extends to -55°C for enhanced low-temperature performance.

All substitute parts maintain ROHS3 compliance and Moisture Sensitivity Level 1 (Unlimited) ratings, ensuring compatibility with standard manufacturing and storage protocols.

Frequently Asked Questions (FAQ)

Q: Can the MM74HC74ASJX be directly replaced with any 74HC74 variant?

A: Yes, all parts sharing the 74HC74 base product number are functionally equivalent. Pin configuration, logic function, and electrical operating ranges are identical across the family. Physical package dimensions may vary between manufacturers, requiring PCB layout verification.

Q: What is the difference between the 0.209" and 0.154" SOIC package widths?

A: Both are 14-SOIC packages with identical pin pitch and electrical performance. The width difference reflects manufacturing tolerance variations between suppliers. PCB footprints must accommodate the specific package width of the selected part. Verify footprint compatibility before design implementation.

Q: Are there performance differences between substitute parts?

A: Propagation delay, clock frequency, and quiescent current vary within the 74HC74 family. The SN74HC74DR offers the fastest propagation delay (15 ns), while CD74HC74M96 provides the lowest clock frequency (50 MHz). These variations do not affect functional interchangeability in standard digital logic applications but may impact timing-critical designs.

Q: Which substitute part offers the best long-term availability?

A: Parts with Active product status provide the highest procurement reliability. The SN74HC74DR, 74HC74D, and CD74HC74M96 are currently active. Avoid parts marked as Discontinued at DiGi Electronics or Obsolete for new designs requiring extended production runs.

Q: Do all substitute parts meet RoHS3 compliance?

A: All listed substitute parts are RoHS3 compliant. Moisture Sensitivity Level 1 (Unlimited) is maintained across all variants, ensuring compatibility with standard surface mount assembly processes.

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