74AC574SCX Equivalent & Substitute Parts

Part Overview

The 74AC574SCX 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 component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement.

The 74AC574SCX operates across a 2V to 6V supply range with a maximum propagation delay of 9.5ns at 5V with 50pF load. Its tri-state, non-inverted output configuration supports standard logic applications requiring edge-triggered data storage and output control.

Key Parameters

Parameter	Value
Manufacturer Part Number	74AC574SCX
Manufacturer	onsemi
Series	74AC
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	153 MHz
Max Propagation Delay @ 5V, 50pF	9.5ns
Voltage Supply Range	2V ~ 6V
Current Output High/Low	24mA / 24mA
Quiescent Current (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

Substitute parts for the 74AC574SCX are classified based on functional and electrical compatibility within the following criteria:

Core Compatibility Parameters:

Type: D-Type flip-flop with 1 element, 8-bit configuration
Output Type: Tri-State, Non-Inverted
Trigger Type: Positive Edge
Package: 20-SOIC (0.295", 7.50mm Width)
Mounting Type: Surface Mount
Voltage Supply Range: Minimum 2V support required
Operating Temperature: Minimum -40°C to 85°C range required

Direct Manufacturer Substitutes maintain identical functional specifications and are sourced from the same or equivalent manufacturers with active product status.

Similar Manufacturer Substitutes operate within the same logic family (74AC or 74AHC series) with compatible electrical characteristics, though may exhibit variations in clock frequency, propagation delay, or quiescent current within acceptable engineering tolerances.

Parametric Equivalents provide functionally identical performance with enhanced specifications (lower propagation delay, reduced quiescent current, or extended temperature range) while maintaining full backward compatibility.

Parameter Comparison

Parameter	74AC574SCX (Main)	MC74AC574DWR2G	MC74AC574DWG	SN74AC374DWR	74AHC574D,118	CD74AC574M96	SN74AC574DWR
Manufacturer	onsemi	onsemi	onsemi	Texas Instruments	Nexperia USA Inc.	Texas Instruments	Texas Instruments
Series	74AC	74AC	74AC	74AC	74AHC	74AC	74AC
Product Status	Obsolete	Active	Active	Active	Active	Active	Active
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
Number of Bits per Element	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
Trigger Type	Positive Edge	Positive Edge	Positive Edge	Positive Edge	Positive Edge	Positive Edge	Positive Edge
Clock Frequency	153 MHz	95 MHz	95 MHz	155 MHz	115 MHz	125 MHz	153 MHz
Max Propagation Delay @ 5V, 50pF	9.5ns	9.5ns	9.5ns	8ns	10.6ns	10.8ns	6ns
Voltage Supply Range	2V ~ 6V	2V ~ 6V	2V ~ 6V	2V ~ 6V	2V ~ 5.5V	1.5V ~ 5.5V	2V ~ 6V
Current Output High/Low	24mA / 24mA	24mA / 24mA	24mA / 24mA	24mA / 24mA	8mA / 8mA	24mA / 24mA	24mA / 24mA
Quiescent Current (Iq)	40 µA	8 µA	8 µA	4 µA	4 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
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
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)
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
RoHS Status	Not specified	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)	3 (168 Hours)	3 (168 Hours)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)

Engineering Selection Recommendations

For Direct Replacement with Active Product Status:

SN74AC574DWR (Texas Instruments) is the primary parametric equivalent, offering identical clock frequency (153 MHz) and voltage supply range (2V ~ 6V) with superior propagation delay (6ns versus 9.5ns) and reduced quiescent current (4 µA versus 40 µA). This part maintains MSL 1 rating and ROHS3 compliance, ensuring compatibility with modern manufacturing and environmental standards.

For Cost-Optimized Substitution:

MC74AC574DWR2G and MC74AC574DWG (onsemi) provide functional equivalence with matching propagation delay (9.5ns) and output current specifications (24mA). Both parts are active products with ROHS3 compliance. MSL 3 rating requires controlled storage conditions (168 hours at 60% relative humidity maximum).

For Extended Temperature Range Applications:

CD74AC574M96 (Texas Instruments) extends operating temperature to -55°C to 125°C and supports lower supply voltage (1.5V minimum). This part accommodates wider environmental specifications while maintaining tri-state, non-inverted output configuration and 24mA output current.

For Reduced Output Current Requirements:

74AHC574D,118 (Nexperia USA Inc.) operates with 8mA output current (versus 24mA in the main part) and extends operating temperature to 125°C. This substitution is suitable for applications where lower output drive capability is acceptable and extended temperature operation is required.

Frequently Asked Questions (FAQ)

Q: Can SN74AC574DWR directly replace 74AC574SCX in existing designs?

A: Yes. SN74AC574DWR maintains identical functional specifications (D-Type, 8-bit, positive edge trigger, tri-state output) and package (20-SOIC). Superior propagation delay (6ns versus 9.5ns) and lower quiescent current (4 µA versus 40 µA) provide performance enhancement without design modification.

Q: What is the difference between 74AC and 74AHC series substitutes?

A: Both series provide D-Type flip-flop functionality in 20-SOIC packages. The 74AC series (74AC574SCX, SN74AC574DWR, CD74AC574M96) supports 2V ~ 6V supply range with 24mA output current. The 74AHC series (74AHC574D,118) operates at 2V ~ 5.5V with reduced 8mA output current and extended temperature range to 125°C. Selection depends on supply voltage availability and output current requirements.

Q: Are there packaging differences between substitute parts?

A: All substitute parts use identical 20-SOIC (0.295", 7.50mm Width) surface mount package. Packaging format variations (Cut Tape, Tube, Tape & Reel) affect procurement and handling but do not impact electrical or mechanical compatibility.

Q: What does MSL 3 rating mean for MC74AC574DWR2G and MC74AC574DWG?

A: MSL 3 indicates 168-hour maximum storage at 60% relative humidity before reflow soldering. These parts require controlled storage conditions. MSL 1 parts (SN74AC574DWR, 74AHC574D,118, CD74AC574M96) have unlimited shelf life and are preferred for applications with extended inventory holding periods.

Q: Can 74AHC574D,118 replace 74AC574SCX in high-current applications?

A: No. 74AHC574D,118 provides 8mA output current versus 24mA in the main part. This substitution is suitable only for applications where lower output drive capability meets design requirements. Verify load impedance and current budget before selection.

Q: Which substitute offers the best performance improvement?

A: SN74AC574DWR provides the most significant performance enhancement with 6ns propagation delay (37% improvement over 9.5ns), 4 µA quiescent current (90% reduction from 40 µA), and maintains full voltage supply range (2V ~ 6V) and output current (24mA) compatibility.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All active substitute parts (MC74AC574DWR2G, MC74AC574DWG, SN74AC374DWR, 74AHC574D,118, CD74AC574M96, SN74AC574DWR) are ROHS3 compliant. The obsolete main part (74AC574SCX) does not specify RoHS status.

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