74ACTQ574PC Equivalent & Substitute Parts

Part Overview

The 74ACTQ574PC is a single-element D-type flip-flop integrated circuit with 8-bit positive edge triggering, manufactured by onsemi in a 20-DIP through-hole package. This logic component is classified as obsolete, making equivalent substitute parts necessary for ongoing system maintenance, repair, and legacy design support. The part operates at 85 MHz clock frequency with tri-state, non-inverted outputs suitable for bus-oriented digital applications.

Substiute Parts

74ACTQ574PC

onsemiIn Stock: 107974ACTQ574PC Datasheet

Current PartRFQ

CD74ACT574E

Harris CorporationIn Stock: 2372CD74ACT574E Datasheet

SimilarRFQ

SN74ACT574N

Texas InstrumentsIn Stock: 1629SN74ACT574N Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 74ACTQ574PC is determined by strict equivalence across the following critical parameters:

Functional Equivalence: All substitute parts must be D-type flip-flops with 1 element, 8 bits per element, positive edge triggering, and tri-state non-inverted outputs.

Electrical Compatibility: Supply voltage range (4.5V ~ 5.5V), output current capability (24 mA minimum for both high and low states), and package type (20-DIP through-hole) must match or exceed the original specification.

Timing Performance: Clock frequency and propagation delay determine functional interchangeability. Substitutes with equal or superior timing characteristics maintain system performance.

Thermal and Environmental Range: Operating temperature range must encompass or exceed the original -40°C ~ 85°C specification to ensure reliability across intended applications.

The 74ACTQ574PC has two qualified substitutes: the CD74ACT574E (Harris Corporation) and the SN74ACT574N (Texas Instruments), both meeting these core substitution criteria.

Parameter Comparison

Engineering Selection Recommendations

SN74ACT574N (Texas Instruments) is the primary substitute for new designs and ongoing production. This part maintains active product status, ensuring long-term availability and supply chain stability. It meets all functional and electrical requirements with equivalent operating temperature range (-40°C ~ 85°C) and superior quiescent current performance (4 µA versus 40 µA). RoHS3 compliance supports modern manufacturing and environmental standards.

CD74ACT574E (Harris Corporation) serves as a secondary substitute where inventory availability or cost considerations apply. This part is obsolete but functionally equivalent, with extended operating temperature range (-55°C ~ 125°C) suitable for harsh environment applications. Lower quiescent current (8 µA) provides power efficiency benefits. Note that RoHS non-compliance may restrict use in regulated applications.

Both substitutes are pin-compatible through-hole 20-DIP packages with identical functional specifications, enabling direct board-level replacement without design modification.

Frequently Asked Questions (FAQ)

Q: Can the SN74ACT574N directly replace the 74ACTQ574PC without circuit modification?

A: Yes. Both parts are functionally equivalent D-type flip-flops with identical pin configurations, output types, supply voltage requirements, and output current ratings. Direct substitution is supported at the board level.

Q: What is the significance of the higher clock frequency (110 MHz) in the substitute parts?

A: The substitute parts (CD74ACT574E and SN74ACT574N) operate at 110 MHz versus 85 MHz for the original 74ACTQ574PC. This represents improved performance capability and does not create compatibility issues in systems designed for the original 85 MHz specification.

Q: Why is the SN74ACT574N preferred over the CD74ACT574E?

A: The SN74ACT574N maintains active product status, ensuring ongoing availability and supply chain support. It also provides lower quiescent current (4 µA) and RoHS3 compliance, meeting modern manufacturing and environmental requirements. The CD74ACT574E is obsolete and RoHS non-compliant.

Q: Are there thermal performance differences between these parts?

A: The CD74ACT574E supports an extended operating temperature range (-55°C ~ 125°C) compared to the 74ACTQ574PC and SN74ACT574N (-40°C ~ 85°C). For applications within the standard -40°C ~ 85°C range, all three parts are thermally equivalent.

Q: What does "tri-state, non-inverted output" mean for substitution purposes?

A: This output configuration allows the flip-flop outputs to assume three states: logic high, logic low, or high-impedance (disabled). Non-inverted means the output directly reflects the stored data state. All substitute parts maintain this identical output behavior.

Q: Is the 20-DIP package format critical for substitution?

A: Yes. The 20-DIP through-hole package is a physical and electrical requirement for direct board-level substitution. All listed substitutes use this identical package format, enabling pin-for-pin replacement.

Q: What is the impact of different input capacitance values (4.5 pF versus 10 pF)?

A: Input capacitance affects circuit loading and timing characteristics. The CD74ACT574E has higher input capacitance (10 pF) compared to the 74ACTQ574PC and SN74ACT574N (4.5 pF). This difference is within normal design margins for standard logic applications and does not prevent substitution.