MM74HCT74MTC Equivalent & Substitute Parts

Part Overview

The MM74HCT74MTC is a dual D-type flip-flop logic integrated circuit manufactured by onsemi in 14-TSSOP surface mount packaging. This device functions as a 2-element D-type flip-flop with complementary outputs, set/preset and reset capabilities, and positive edge triggering. The part is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity. Substitute parts must maintain functional equivalence through matching logic family characteristics, package compatibility, and electrical performance within specified operating ranges.

Key Parameters

Parameter	MM74HCT74MTC
Manufacturer	onsemi
Series	74HCT
Type	D-Type Flip-Flop
Number of Elements	2
Number of Bits per Element	1
Output Type	Complementary
Trigger Type	Positive Edge
Clock Frequency	27 MHz
Max Propagation Delay @ V, Max CL	35ns @ 5V, 50pF
Voltage Supply Range	4.5V ~ 5.5V
Current - Output High, Low	4.8mA, 4.8mA
Current - Quiescent (Iq)	2 µA
Input Capacitance	5 pF
Operating Temperature	-40°C ~ 85°C
Package / Case	14-TSSOP (0.173", 4.40mm Width)
Mounting Type	Surface Mount
Product Status	Obsolete
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution logic for the MM74HCT74MTC is based on the following criteria:

Functional Equivalence: All substitute parts must be dual D-type flip-flops with complementary outputs, set/preset and reset functions, and positive edge triggering.

Package Compatibility: Primary substitutes maintain the 14-TSSOP (0.173", 4.40mm Width) surface mount package. The SN74HCT74DBR variant uses 14-SSOP (0.209", 5.30mm Width) and is listed for reference but requires PCB layout verification.

Logic Family Compatibility: Substitutes span three logic families—74HCT, 74HC, and 74AHCT/74VHCT—each with distinct electrical characteristics. 74HCT and 74AHCT families maintain 4.5V ~ 5.5V supply compatibility with the original part. The 74HC family operates across 2V ~ 6V, providing broader supply range flexibility. The 74VHCT family also operates at 4.5V ~ 5.5V.

Electrical Performance: Substitutes are grouped by propagation delay and clock frequency. The original part specifies 27 MHz clock frequency and 35ns maximum propagation delay. Faster variants (74AHCT, 74VHCT series) offer 140 MHz clock frequency and 8.8ns propagation delay, suitable for higher-speed applications. The 74HC variant provides 35 MHz clock frequency and 17ns propagation delay as a mid-range option.

Product Status: Active substitutes ensure long-term availability. Discontinued or obsolete variants are noted for legacy system support only.

Parameter Comparison

Part Number	Manufacturer	Series	Clock Frequency	Max Propagation Delay @ V, Max CL	Voltage Supply	Current Output High/Low	Operating Temperature	Package	Product Status
MM74HCT74MTC	onsemi	74HCT	27 MHz	35ns @ 5V, 50pF	4.5V ~ 5.5V	4.8mA, 4.8mA	-40°C ~ 85°C	14-TSSOP	Obsolete
MC74HC74ADTR2G	onsemi	74HC	35 MHz	17ns @ 6V, 50pF	2V ~ 6V	5.2mA, 5.2mA	-55°C ~ 125°C	14-TSSOP	Active
MC74VHCT74ADTR2G	onsemi	74VHCT	140 MHz	8.8ns @ 5V, 50pF	4.5V ~ 5.5V	8mA, 8mA	-55°C ~ 125°C	14-TSSOP	Active
74HCT74PW,118	Nexperia USA Inc.	74HCT	59 MHz	44ns @ 4.5V, 50pF	4.5V ~ 5.5V	4mA, 4mA	-40°C ~ 125°C	14-TSSOP	Active
SN74AHCT74MPWREP	Texas Instruments	74AHCT	140 MHz	8.8ns @ 5V, 50pF	4.5V ~ 5.5V	8mA, 8mA	-55°C ~ 125°C	14-TSSOP	Active
SN74AHCT74PW	Texas Instruments	74AHCT	140 MHz	11.4ns @ 5V, 50pF	4.5V ~ 5.5V	8mA, 8mA	-40°C ~ 125°C	14-TSSOP	Discontinued at DiGi Electronics
SN74AHCT74PWR	Texas Instruments	74AHCT	140 MHz	8.8ns @ 5V, 50pF	4.5V ~ 5.5V	8mA, 8mA	-40°C ~ 125°C	14-TSSOP	Active
SN74AHCT74QPWRG4Q1	Texas Instruments	74AHCT	140 MHz	8.8ns @ 5V, 50pF	4.5V ~ 5.5V	8mA, 8mA	-40°C ~ 125°C	14-TSSOP	Active
SN74AHCT74QPWRQ1	Texas Instruments	74AHCT	140 MHz	8.8ns @ 5V, 50pF	4.5V ~ 5.5V	8mA, 8mA	-40°C ~ 125°C	14-TSSOP	Active
SN74HCT74DBR	Texas Instruments	74HCT	46 MHz	25ns @ 5.5V, 50pF	4.5V ~ 5.5V	4mA, 4mA	-40°C ~ 85°C	14-SSOP	Active
SN74HCT74PW	Texas Instruments	74HCT	46 MHz	25ns @ 5.5V, 50pF	4.5V ~ 5.5V	4mA, 4mA	-40°C ~ 85°C	14-TSSOP	Discontinued at DiGi Electronics

Engineering Selection Recommendations

For Direct Replacement (Same Performance Class):

The 74HCT74PW,118 from Nexperia USA Inc. is the primary direct replacement. It maintains 74HCT series logic family compatibility, 4.5V ~ 5.5V supply voltage, 14-TSSOP package, and extended operating temperature range (-40°C ~ 125°C). This part is active and ROHS3 compliant.

The SN74HCT74PW from Texas Instruments provides equivalent 74HCT functionality in 14-TSSOP packaging with matching supply voltage and temperature range. Although discontinued at DiGi Electronics, inventory remains available. The SN74HCT74DBR variant uses 14-SSOP packaging and is active; PCB layout verification is required due to package footprint differences.

For Enhanced Performance (Higher Speed Applications):

The SN74AHCT74MPWREP, SN74AHCT74PWR, SN74AHCT74QPWRG4Q1, and SN74AHCT74QPWRQ1 from Texas Instruments, along with MC74VHCT74ADTR2G from onsemi, offer 140 MHz clock frequency and 8.8ns propagation delay. These parts maintain 4.5V ~ 5.5V supply compatibility and 14-TSSOP packaging. The automotive-qualified variants (QPWRG4Q1, QPWRQ1) include AEC-Q100 certification. All are active products.

For Broader Supply Range Compatibility:

The MC74HC74ADTR2G from onsemi operates across 2V ~ 6V supply voltage, providing flexibility for mixed-voltage systems. It delivers 35 MHz clock frequency and 17ns propagation delay with extended operating temperature (-55°C ~ 125°C). This part is active and ROHS3 compliant.

Compliance and Certification:

All listed substitutes are ROHS3 compliant and REACH unaffected. Moisture sensitivity level is MSL 1 (unlimited) for standard variants, with MSL 3 (168 hours) for SN74AHCT74QPWRQ1. Automotive applications requiring AEC-Q100 qualification should specify SN74AHCT74QPWRG4Q1 or SN74AHCT74QPWRQ1.

Frequently Asked Questions (FAQ)

Q: Can I use a 74HC series part as a direct replacement for the MM74HCT74MTC?

A: The MC74HC74ADTR2G is functionally equivalent but operates across a wider supply range (2V ~ 6V) compared to the original 4.5V ~ 5.5V specification. It offers faster propagation delay (17ns vs. 35ns) and extended temperature range (-55°C ~ 125°C). Substitution is valid if your circuit design accommodates the broader supply voltage range.

Q: What is the difference between 74HCT, 74AHCT, and 74VHCT logic families?

A: All three families are TTL-compatible CMOS logic with 4.5V ~ 5.5V supply voltage. The 74AHCT and 74VHCT families offer significantly higher clock frequency (140 MHz vs. 27-59 MHz) and faster propagation delay (8.8ns vs. 25-44ns). The 74HCT family provides the closest electrical match to the original part. Selection depends on timing requirements and system performance specifications.

Q: Are the 14-TSSOP and 14-SSOP packages interchangeable?

A: No. The 14-TSSOP (0.173", 4.40mm width) and 14-SSOP (0.209", 5.30mm width) packages have different footprints. The SN74HCT74DBR uses 14-SSOP packaging and requires PCB layout verification and potential rework. For direct PCB compatibility, select parts specified in 14-TSSOP packaging.

Q: Which substitute part should I use for automotive applications?

A: The SN74AHCT74QPWRG4Q1 and SN74AHCT74QPWRQ1 from Texas Instruments are AEC-Q100 qualified for automotive use. Both maintain 14-TSSOP packaging, 4.5V ~ 5.5V supply voltage, and 140 MHz clock frequency. The QPWRQ1 variant has MSL 3 (168 hours) moisture sensitivity.

Q: What is the impact of higher propagation delay specifications on circuit timing?

A: The original MM74HCT74MTC specifies 35ns maximum propagation delay. Substitutes with lower propagation delay (8.8-17ns) are faster and backward compatible. Substitutes with higher propagation delay (44ns) may impact timing-critical circuits. Verify that your circuit design accommodates the specified propagation delay before substitution.

Q: Are all listed substitutes currently in stock?

A: Product availability varies. Active products (MC74HC74ADTR2G, MC74VHCT74ADTR2G, 74HCT74PW,118, SN74AHCT74MPWREP, SN74AHCT74PWR, SN74AHCT74QPWRG4Q1, SN74AHCT74QPWRQ1, SN74HCT74DBR) have confirmed inventory. Discontinued variants (SN74AHCT74PW, SN74HCT74PW) may have limited availability. Verify current stock status with your supplier.

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