74ACT574SCX Equivalent & Substitute Parts

Part Overview

The 74ACT574SCX 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, which necessitates identification of equivalent and substitute components for ongoing design support and procurement.

The 74ACT574SCX operates as a standard D-type flip-flop with tri-state, non-inverted outputs, suitable for digital logic applications requiring edge-triggered data capture and storage. Due to its obsolete status, direct replacements from active product lines are required for new designs and production continuity.

Key Parameters

Parameter	Value
Manufacturer Part Number	74ACT574SCX
Manufacturer	onsemi
Series	74ACT
Type	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	110 MHz
Max Propagation Delay @ 5V, 50pF	11 ns
Current - Output High/Low	24 mA / 24 mA
Voltage - Supply	4.5V ~ 5.5V
Current - Quiescent (Iq)	40 µA
Input Capacitance	4.5 pF
Operating Temperature	-40°C ~ 85°C
Package / Case	20-SOIC (0.295", 7.50mm Width)
Mounting Type	Surface Mount
Product Status	Obsolete
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution of the 74ACT574SCX is determined by strict adherence to the following electrical and mechanical parameters:

Critical Matching Parameters:

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
Voltage Supply Range: 4.5V ~ 5.5V
Package / Case: 20-SOIC (0.295", 7.50mm Width)
Mounting Type: Surface Mount

Allowable Variations:

Clock Frequency: 100 MHz or higher
Max Propagation Delay: 11.2 ns or lower
Current - Output High/Low: 8 mA or higher
Current - Quiescent (Iq): Any value
Operating Temperature: -40°C minimum and 85°C maximum or wider range
Product Status: Active or Discontinued (not Obsolete)

Substitute parts are grouped into two categories: Direct Manufacturer Substitutes (functionally identical with active status) and Similar Parts (compatible but with minor parameter variations or different manufacturers).

Parameter Comparison

Parameter	74ACT574SCX (Main)	MC74ACT574DWR2G	SN74ACT574DW	SN74ACT574DWR	74AHCT574D,118	CD74ACT574M96	MC74ACT574DWG	SN74ACT574NSR
Manufacturer	onsemi	onsemi	Texas Instruments	Texas Instruments	NXP USA Inc.	Texas Instruments	onsemi	Texas Instruments
Series	74ACT	74ACT	74ACT	74ACT	74AHCT	74ACT	74ACT	74ACT
Type	D-Type	D-Type	D-Type	D-Type	D-Type	D-Type	D-Type	D-Type
Number of Elements	1	1	1	1	1	1	1	1
Number of Bits per Element	8	8	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	Tri-State, Non-Inverted	Tri-State, Non-Inverted
Trigger Type	Positive Edge	Positive Edge	Positive Edge	Positive Edge	Positive Edge	Positive Edge	Positive Edge	Positive Edge
Clock Frequency	110 MHz	100 MHz	110 MHz	110 MHz	115 MHz	110 MHz	100 MHz	110 MHz
Max Propagation Delay @ 5V, 50pF	11 ns	11 ns	11 ns	11 ns	10.6 ns	11.2 ns	11 ns	11 ns
Current - Output High, Low	24 mA, 24 mA	24 mA, 24 mA	24 mA, 24 mA	24 mA, 24 mA	8 mA, 8 mA	24 mA, 24 mA	24 mA, 24 mA	24 mA, 24 mA
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	4.5V ~ 5.5V	4.5V ~ 5.5V
Current - Quiescent (Iq)	40 µA	8 µA	4 µA	4 µA	4 µA	8 µA	8 µA	4 µA
Input Capacitance	4.5 pF	4.5 pF	4.5 pF	4.5 pF	3 pF	10 pF	4.5 pF	4.5 pF
Operating Temperature	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 125°C	-55°C ~ 125°C	-40°C ~ 85°C	-40°C ~ 85°C
Package / Case	20-SOIC (0.295", 7.50mm Width)	20-SOIC (0.295", 7.50mm Width)	20-SOIC (0.295", 7.50mm Width)	20-SOIC (0.295", 7.50mm Width)	20-SOIC (0.295", 7.50mm Width)	20-SOIC (0.295", 7.50mm Width)	20-SOIC (0.295", 7.50mm Width)	20-SOIC (0.209", 5.30mm Width)
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Product Status	Obsolete	Active	Discontinued at DiGi Electronics	Active	Active	Active	Active	Active
RoHS Status	Not specified	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	Not specified	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)	3 (168 Hours)	1 (Unlimited)	1 (Unlimited)	Not specified	1 (Unlimited)	3 (168 Hours)	1 (Unlimited)

Engineering Selection Recommendations

Primary Substitutes (Active Status, Full Compatibility):

SN74ACT574DWR from Texas Instruments is the recommended primary substitute. This part maintains active product status, meets all electrical specifications of the 74ACT574SCX, and carries ROHS3 compliance with MSL 1 rating. It is available in high inventory (18,709 pcs) in Cut Tape and Digi-Reel packaging.

MC74ACT574DWR2G from onsemi is an alternative primary substitute with active status and ROHS3 compliance. It meets all critical electrical parameters and is available in Tape & Reel packaging with 2,092 pcs in stock.

Secondary Substitutes (Extended Temperature or Improved Performance):

CD74ACT574M96 from Texas Instruments offers extended operating temperature range (-55°C to 125°C) compared to the original part (-40°C to 85°C), providing broader environmental coverage. This part is active and ROHS3 compliant with the highest inventory availability (50,300 pcs).

Alternative Series (Different Electrical Characteristics):

74AHCT574D,118 from NXP USA Inc. represents a different logic family (74AHCT vs. 74ACT) with reduced output current capability (8 mA vs. 24 mA) but improved propagation delay (10.6 ns vs. 11 ns) and extended operating temperature (-40°C to 125°C). This part is suitable only for applications where lower output current is acceptable.

Package Variant Consideration:

SN74ACT574NSR from Texas Instruments uses a narrower 20-SOIC package (0.209" vs. 0.295" width). This part is electrically equivalent but requires PCB layout verification due to different package dimensions.

Frequently Asked Questions (FAQ)

Q: Can I directly replace 74ACT574SCX with SN74ACT574DWR?

A: Yes. SN74ACT574DWR is a direct electrical and functional equivalent. Both parts share identical logic function, pin configuration, electrical specifications, and 20-SOIC package dimensions. The primary difference is product status: SN74ACT574DWR is active while 74ACT574SCX is obsolete.

Q: What is the difference between 74ACT574SCX and MC74ACT574DWR2G?

A: Both parts are functionally equivalent D-type flip-flops with 8-bit tri-state outputs. The main differences are: MC74ACT574DWR2G has lower quiescent current (8 µA vs. 40 µA), higher MSL rating (3 vs. 1), and is supplied in Tape & Reel packaging. Electrical performance and operating temperature ranges are identical.

Q: Why does CD74ACT574M96 have different input capacitance (10 pF vs. 4.5 pF)?

A: Input capacitance variation is a characteristic difference between manufacturing processes and part revisions. Both values fall within acceptable ranges for standard logic applications. The higher input capacitance of CD74ACT574M96 does not affect functional compatibility but may require circuit timing verification in high-frequency applications.

Q: Is 74AHCT574D,118 compatible with 74ACT574SCX?

A: 74AHCT574D,118 is functionally compatible but belongs to a different logic family (74AHCT vs. 74ACT). The key limitation is reduced output current (8 mA vs. 24 mA). It is suitable only for applications where lower drive capability is acceptable. Verify load requirements before substitution.

Q: Can I use SN74ACT574NSR as a drop-in replacement?

A: SN74ACT574NSR is electrically equivalent but uses a narrower 20-SOIC package (0.209" width vs. 0.295" width). PCB layout and footprint verification is required. Pin configuration and electrical specifications are identical, but physical package dimensions differ.

Q: What does MSL 1 vs. MSL 3 mean for my application?

A: MSL (Moisture Sensitivity Level) indicates moisture absorption limits during storage and handling. MSL 1 allows unlimited shelf life without baking. MSL 3 requires baking after 168 hours of exposure to ambient humidity. For standard manufacturing environments with proper storage, both ratings are acceptable. MSL 3 parts require additional handling procedures if storage exceeds 168 hours.

Q: Are all substitute parts ROHS3 compliant?

A: Most active substitutes (SN74ACT574DWR, MC74ACT574DWR2G, CD74ACT574M96, MC74ACT574DWG, SN74ACT574NSR) are ROHS3 compliant. The original 74ACT574SCX and 74AHCT574D,118 do not specify RoHS status. Verify RoHS compliance requirements for your application before final part selection.

Q: Which substitute has the best availability?

A: CD74ACT574M96 has the highest inventory (50,300 pcs), followed by SN74ACT574DWR (18,709 pcs). Both parts are suitable for high-volume production requirements.

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