MM74HCT574N Equivalent & Substitute Parts

Part Overview

The MM74HCT574N is a single 8-bit D-type flip-flop logic integrated circuit in a 20-DIP package manufactured by onsemi. This device features tri-state, non-inverted outputs and operates at a clock frequency of 33 MHz with a maximum propagation delay of 30ns at 5V with 50pF load. The part is currently obsolete, making equivalent substitutes necessary for new designs or component replacement in legacy systems. Substitute parts must maintain functional compatibility through matching logic family (74HCT series), package type (20-DIP), and core electrical specifications.

Key Parameters

Parameter	Value
Logic Family	74HCT
Function	D-Type Flip-Flop, 1 Element, 8 Bit
Output Type	Tri-State, Non-Inverted
Package Type	20-DIP (0.300", 7.62mm)
Mounting	Through Hole
Voltage Supply Range	4.5V ~ 5.5V
Operating Temperature	-40°C ~ 85°C
Trigger Type	Positive Edge

Substitute Part Grouping Explanation

Substitution for the MM74HCT574N is based on strict equivalence across the following criteria:

Primary Substitution Requirements:

Identical logic family designation (74HCT series)
Matching functional specification (D-type flip-flop, 1 element, 8-bit configuration)
Identical output type (tri-state, non-inverted)
Same package type and pin count (20-DIP)
Compatible voltage supply range (4.5V ~ 5.5V)
Positive edge trigger operation

Acceptable Parameter Variations:

Clock frequency may exceed the original specification
Maximum propagation delay may vary within acceptable limits for the 74HCT family
Output current ratings may differ while maintaining tri-state capability
Operating temperature range may be extended
Input capacitance variations are acceptable within logic family standards

The two identified substitutes—CD74HCT574E (Texas Instruments) and SN74HCT574N (Texas Instruments)—meet all primary requirements and are functionally interchangeable with the MM74HCT574N in 20-DIP through-hole applications.

Parameter Comparison

Parameter	MM74HCT574N (onsemi)	CD74HCT574E (TI)	SN74HCT574N (TI)
Manufacturer	onsemi	Texas Instruments	Texas Instruments
Product Status	Obsolete	Active	Active
Logic Family	74HCT	74HCT	74HCT
Type	D-Type Flip-Flop	D-Type Flip-Flop	D-Type Flip-Flop
Number of Elements	1	1	1
Number of Bits per Element	8	8	8
Output Type	Tri-State, Non-Inverted	Tri-State, Non-Inverted	Tri-State, Non-Inverted
Clock Frequency	33 MHz	60 MHz	40 MHz
Max Propagation Delay	30ns @ 5V, 50pF	33ns @ 4.5V, 50pF	47ns @ 5.5V, 150pF
Current - Output High, Low	7.2mA, 7.2mA	6mA, 6mA	6mA, 6mA
Voltage - Supply	4.5V ~ 5.5V	4.5V ~ 5.5V	4.5V ~ 5.5V
Current - Quiescent (Iq)	8 µA	8 µA	8 µA
Trigger Type	Positive Edge	Positive Edge	Positive Edge
Operating Temperature	-40°C ~ 85°C	-55°C ~ 125°C	-40°C ~ 85°C
Package / Case	20-DIP (0.300", 7.62mm)	20-DIP (0.300", 7.62mm)	20-DIP (0.300", 7.62mm)
Mounting Type	Through Hole	Through Hole	Through Hole
RoHS Status	Not specified	ROHS3 Compliant	ROHS3 Compliant
REACH Status	REACH Unaffected	REACH Unaffected	REACH Unaffected

Engineering Selection Recommendations

CD74HCT574E (Texas Instruments): This substitute offers active product status with extended operating temperature range (-55°C ~ 125°C) and higher clock frequency (60 MHz). It is ROHS3 compliant and suitable for applications requiring enhanced temperature performance. The propagation delay specification (33ns @ 4.5V, 50pF) is comparable to the original part. This option is recommended for new designs or applications with demanding environmental specifications.

SN74HCT574N (Texas Instruments): This substitute maintains the same operating temperature range as the original MM74HCT574N (-40°C ~ 85°C) and offers active product status. It provides the highest inventory availability among substitutes. The clock frequency (40 MHz) exceeds the original specification. This option is recommended for direct replacement in existing designs where temperature range compatibility is critical and high component availability is advantageous.

Both substitutes are REACH compliant and maintain full functional equivalence with the MM74HCT574N in 20-DIP through-hole applications.

Frequently Asked Questions (FAQ)

Q: Can CD74HCT574E and SN74HCT574N be used interchangeably with MM74HCT574N?

A: Yes. Both parts are functionally equivalent D-type flip-flops in the 74HCT logic family with identical 20-DIP package configuration, tri-state non-inverted outputs, and 4.5V ~ 5.5V supply voltage compatibility. Pin-for-pin substitution is direct.

Q: What is the primary difference between the two substitute options?

A: CD74HCT574E offers extended operating temperature range (-55°C ~ 125°C) and higher clock frequency (60 MHz), while SN74HCT574N maintains the original temperature range (-40°C ~ 85°C) with greater inventory availability. Both are active products from Texas Instruments.

Q: Are there package compatibility concerns?

A: No. All three parts use identical 20-DIP (0.300", 7.62mm) through-hole packages. Direct socket substitution is possible without PCB modification.

Q: Does the higher clock frequency in the substitutes affect compatibility?

A: No. Higher clock frequency specifications indicate enhanced performance capability. The substitutes will operate correctly in applications designed for the original 33 MHz specification.

Q: What compliance certifications apply to the substitutes?

A: Both CD74HCT574E and SN74HCT574N are ROHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements.

Q: Why is the MM74HCT574N listed as obsolete?

A: The MM74HCT574N is no longer manufactured by onsemi. The identified substitutes from Texas Instruments provide equivalent functionality with active product status and ongoing availability.

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