DM74LS74AN Equivalent & Substitute Parts

Part Overview

The DM74LS74AN is a dual D-type flip-flop logic integrated circuit manufactured by onsemi, housed in a 14-DIP package. This component 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 substitutes necessary for ongoing production and maintenance applications where this logic function is required.

Substiute Parts

DM74LS74AN

onsemiIn Stock: 1688DM74LS74AN Datasheet

Current PartRFQ

SN74LS74AN

Texas InstrumentsIn Stock: 3280SN74LS74AN Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the DM74LS74AN is determined by strict equivalence across the following critical parameters:

Functional Equivalence: The substitute must be a D-type flip-flop with 2 elements, 1 bit per element, complementary outputs, set/preset and reset functions, and positive edge triggering.

Electrical Compatibility: Supply voltage range (4.75V ~ 5.25V), output current specifications (400µA high, 8mA low), and quiescent current (8mA) must match or be compatible with the original design.

Package Compatibility: The substitute must use the same 14-DIP (0.300", 7.62mm) through-hole package to ensure direct PCB compatibility without layout modifications.

Logic Series: Both parts belong to the 74LS logic family, ensuring TTL-level signal compatibility and timing characteristics suitable for the same applications.

The SN74LS74AN from Texas Instruments meets all these criteria and qualifies as a direct substitute.

Parameter Comparison

Engineering Selection Recommendations

The SN74LS74AN from Texas Instruments is the direct substitute for the obsolete DM74LS74AN. Both parts share identical functional specifications, electrical parameters, and package dimensions, enabling pin-for-pin replacement without circuit modifications.

The SN74LS74AN offers additional advantages: it maintains active product status, ensuring long-term availability and supply chain reliability. The part is ROHS3 compliant, meeting modern environmental and regulatory requirements. The higher clock frequency specification (33 MHz versus 20 MHz) and improved propagation delay characteristics provide performance headroom for existing designs.

For applications requiring RoHS compliance or long-term component availability, the SN74LS74AN is the recommended selection. The electrical and functional equivalence ensures seamless integration into existing designs originally specified for the DM74LS74AN.

Frequently Asked Questions (FAQ)

Q: Can the SN74LS74AN replace the DM74LS74AN in existing designs?

A: Yes. Both parts are functionally and electrically equivalent D-type flip-flops with identical pin configurations, supply voltage ranges, output current ratings, and operating temperature specifications. Direct substitution is possible without circuit modifications.

Q: Are there package differences between these parts?

A: No. Both the DM74LS74AN and SN74LS74AN use the 14-DIP (0.300", 7.62mm) through-hole package. Pin spacing, lead configuration, and PCB footprint are identical, enabling direct board-level replacement.

Q: What is the significance of the higher clock frequency in the SN74LS74AN?

A: The SN74LS74AN specifies 33 MHz maximum clock frequency compared to 20 MHz for the DM74LS74AN. This represents improved performance margin and does not affect compatibility. Designs operating at or below 20 MHz will function correctly with the substitute part.

Q: Does RoHS compliance affect electrical performance?

A: No. ROHS3 compliance in the SN74LS74AN reflects manufacturing process changes to eliminate restricted substances. Electrical characteristics, logic function, and circuit behavior remain identical to the non-compliant DM74LS74AN.

Q: Are there supply chain considerations for selecting the substitute?

A: Yes. The DM74LS74AN is classified as obsolete, indicating limited or discontinued availability. The SN74LS74AN maintains active product status from Texas Instruments, ensuring reliable long-term supply for production and maintenance applications.