74ACTQ574SCX Equivalent & Substitute Parts

Part Overview

The 74ACTQ574SCX is a D-type flip-flop logic integrated circuit manufactured by onsemi, featuring 1 element with 8-bit positive edge triggering in a 20-SOIC package. This part is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement continuity. The device operates at 85 MHz clock frequency with 9ns maximum propagation delay at 5V and 50pF load, suitable for digital logic applications requiring edge-triggered storage and tri-state output capability.

Key Parameters

Parameter	Value
Manufacturer Part Number	74ACTQ574SCX
Manufacturer	onsemi
Category	Logic
Package / Case	20-SOIC (0.295", 7.50mm Width)
Function	Standard D-Type Flip-Flop
Number of Elements	1
Number of Bits per Element	8
Output Type	Tri-State, Non-Inverted
Trigger Type	Positive Edge
Clock Frequency	85 MHz
Max Propagation Delay @ 5V, 50pF	9ns
Voltage - Supply	4.5V ~ 5.5V
Current - Output High, Low	24mA, 24mA
Current - Quiescent (Iq)	40 µA
Input Capacitance	4.5 pF
Operating Temperature	-40°C ~ 85°C (TA)
Mounting Type	Surface Mount
Product Status	Obsolete
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution eligibility for the 74ACTQ574SCX is determined by the following critical parameters:

Functional equivalence: D-type flip-flop, 1 element, 8-bit configuration, positive edge trigger, tri-state non-inverted output
Package compatibility: 20-SOIC form factor (mechanical fit and pin assignment)
Electrical compatibility: Supply voltage range 4.5V ~ 5.5V, output drive capability 24mA minimum
Timing performance: Clock frequency and propagation delay must meet or exceed application requirements
Operating temperature range: Must support -40°C ~ 85°C minimum

All substitute parts listed maintain functional and electrical equivalence within these parameters. Variations in quiescent current, propagation delay, and product status are noted but do not preclude substitution when application requirements are satisfied.

Parameter Comparison

Parameter	74ACTQ574SCX	MC74ACT574DWR2G	CD74ACT574M96	MC74ACT574DWG	SN74ACT574DWR	SN74ACT574NSR
Manufacturer	onsemi	onsemi	Texas Instruments	onsemi	Texas Instruments	Texas Instruments
Package / Case	20-SOIC (0.295", 7.50mm)	20-SOIC (0.295", 7.50mm)	20-SOIC (0.295", 7.50mm)	20-SOIC (0.295", 7.50mm)	20-SOIC (0.295", 7.50mm)	20-SOIC (0.209", 5.30mm)
Function	Standard D-Type	Standard D-Type	Standard D-Type	Standard D-Type	Standard D-Type	Standard D-Type
Number of Bits	8	8	8	8	8	8
Output Type	Tri-State, Non-Inverted	Tri-State, Non-Inverted	Tri-State, Non-Inverted	Tri-State, Non-Inverted	Tri-State, Non-Inverted	Tri-State, Non-Inverted
Trigger Type	Positive Edge	Positive Edge	Positive Edge	Positive Edge	Positive Edge	Positive Edge
Clock Frequency	85 MHz	100 MHz	110 MHz	100 MHz	110 MHz	110 MHz
Max Propagation Delay @ 5V, 50pF	9ns	11ns	11.2ns	11ns	11ns	11ns
Voltage - Supply	4.5V ~ 5.5V	4.5V ~ 5.5V	4.5V ~ 5.5V	4.5V ~ 5.5V	4.5V ~ 5.5V	4.5V ~ 5.5V
Current - Output High, Low	24mA, 24mA	24mA, 24mA	24mA, 24mA	24mA, 24mA	24mA, 24mA	24mA, 24mA
Current - Quiescent (Iq)	40 µA	8 µA	8 µA	8 µA	4 µA	4 µA
Input Capacitance	4.5 pF	4.5 pF	10 pF	4.5 pF	4.5 pF	4.5 pF
Operating Temperature	-40°C ~ 85°C	-40°C ~ 85°C	-55°C ~ 125°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C
Product Status	Obsolete	Active	Obsolete	Active	Active	Active
RoHS Status	Not specified	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)	3 (168 Hours)	1 (Unlimited)	3 (168 Hours)	1 (Unlimited)	1 (Unlimited)

Engineering Selection Recommendations

Primary substitutes for active production designs:

MC74ACT574DWR2G and SN74ACT574DWR are recommended as primary substitutes. Both are active products with ROHS3 compliance, higher clock frequency (100-110 MHz), and lower quiescent current than the original 74ACTQ574SCX. MC74ACT574DWR2G is supplied in Tape & Reel packaging, while SN74ACT574DWR is available in Cut Tape & Digi-Reel format.

Extended temperature range alternative:

CD74ACT574M96 (Texas Instruments) supports -55°C ~ 125°C operating temperature, exceeding the original specification. This part is active and ROHS3 compliant, suitable for applications requiring extended thermal performance.

Package width consideration:

SN74ACT574NSR features a narrower 20-SOIC package (0.209" width versus 0.295"), requiring PCB layout verification before substitution. This part is active and ROHS3 compliant with superior quiescent current performance (4 µA).

Obsolete design support:

CD74ACT574M is available as an obsolete alternative with extended temperature range (-55°C ~ 125°C) and MSL 1 rating, suitable for legacy system maintenance where procurement of the original 74ACTQ574SCX is not feasible.

Frequently Asked Questions (FAQ)

Q: Can I substitute any of these parts directly into a design using 74ACTQ574SCX?

A: Yes, all listed substitute parts maintain functional and electrical equivalence. Verify that your application does not depend on the specific propagation delay (9ns) of the original part, as substitutes range from 11ns to 11.2ns. Package width must also be confirmed, particularly for SN74ACT574NSR.

Q: What is the difference between the onsemi and Texas Instruments versions?

A: Both manufacturers produce functionally equivalent 74ACT574 logic devices. Texas Instruments versions (CD74ACT574M96, SN74ACT574DWR, SN74ACT574NSR) offer higher clock frequency (110 MHz) and extended temperature range options. onsemi versions (MC74ACT574DWR2G, MC74ACT574DWG) are available in active production status with standard temperature range.

Q: Why does the 74ACTQ574SCX show 40 µA quiescent current while substitutes show 4-8 µA?

A: The original 74ACTQ574SCX is an obsolete part with different process technology. Substitute parts utilize modern manufacturing, resulting in significantly lower power consumption. This is a performance improvement with no functional impact.

Q: Is the package width difference between 0.295" and 0.209" critical?

A: Package width affects PCB footprint and board layout. SN74ACT574NSR (0.209" width) requires layout verification before substitution. If your PCB is designed for the standard 0.295" width, use MC74ACT574DWR2G, MC74ACT574DWG, or SN74ACT574DWR instead.

Q: What does MSL 1 versus MSL 3 mean for my supply chain?

A: MSL (Moisture Sensitivity Level) 1 parts have unlimited shelf life under standard storage conditions. MSL 3 parts (MC74ACT574DWR2G, MC74ACT574DWG) require baking after 168 hours of exposure to ambient humidity. For long-term inventory, MSL 1 parts are preferred.

Q: Are all substitutes ROHS3 compliant?

A: Yes, all active substitute parts listed are ROHS3 compliant. The original 74ACTQ574SCX does not specify RoHS status due to its obsolete classification.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message