DM74LS27N Equivalent & Substitute Parts

Part Overview

The DM74LS27N is a NOR Gate IC with 3 channels and 3 inputs per channel, manufactured by onsemi in a 14-MDIP package. This component is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production requirements. The DM74LS27N operates within the 74LS logic family standard, providing TTL-compatible switching functionality for digital logic applications.

Substiute Parts

DM74LS27N

onsemiIn Stock: 9583DM74LS27N Datasheet

Current PartRFQ

SN74LS27N

Texas InstrumentsIn Stock: 13726SN74LS27N Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the DM74LS27N is determined by strict equivalence across the following critical parameters:

• Logic Type: NOR Gate (3 channel, 3 input configuration)
• Voltage Supply Range: 4.75V ~ 5.25V
• Input Logic Levels: Low 0.8V, High 2V
• Output Current Specifications: 400µA (high), 8mA (low)
• Operating Temperature Range: 0°C ~ 70°C
• Package Type: 14-DIP through-hole mounting
• Base Product Number: 74LS27 series

The SN74LS27N from Texas Instruments meets all these parameters and qualifies as a direct substitute. Both parts share identical functional specifications, electrical characteristics, and physical packaging, enabling pin-for-pin replacement in existing designs.

Parameter Comparison

Engineering Selection Recommendations

The SN74LS27N from Texas Instruments is the primary substitute for the obsolete DM74LS27N. Selection is based on the following factors:

Product Status: The DM74LS27N is obsolete, while the SN74LS27N maintains active production status, ensuring long-term availability and supply chain reliability.

Compliance: The SN74LS27N is ROHS3 compliant, meeting current environmental and regulatory requirements. The DM74LS27N is RoHS non-compliant, which may present restrictions in certain applications and jurisdictions.

Electrical Equivalence: Both parts operate identically within the specified voltage supply range, input logic levels, and output current parameters. The SN74LS27N demonstrates improved propagation delay performance (15ns versus 18ns), providing enhanced speed characteristics while maintaining full functional compatibility.

Physical Compatibility: Both components use identical 14-DIP through-hole packaging, enabling direct socket replacement without PCB modifications.

Frequently Asked Questions (FAQ)

Q: Can the SN74LS27N replace the DM74LS27N in existing designs?

A: Yes. The SN74LS27N is a direct pin-for-pin substitute. Both parts share identical logic function, voltage supply range, input/output specifications, and 14-DIP package configuration. No circuit modifications are required.

Q: What is the difference in propagation delay between these parts?

A: The SN74LS27N has a maximum propagation delay of 15ns at 5V with 15pF load, compared to 18ns at 5V with 50pF load for the DM74LS27N. The SN74LS27N offers faster switching performance.

Q: Why is RoHS compliance important for this substitution?

A: RoHS compliance restricts hazardous substances in electrical equipment. The SN74LS27N is ROHS3 compliant, meeting current environmental standards. The obsolete DM74LS27N is non-compliant, which may limit its use in new designs and certain markets.

Q: Are there any package differences between these parts?

A: No. Both the DM74LS27N and SN74LS27N use the same 14-DIP (0.300", 7.62mm) through-hole package, ensuring mechanical and electrical compatibility.

Q: What supply voltage range do these parts require?

A: Both parts operate within 4.75V to 5.25V, standard for 74LS TTL logic family components. This range accommodates typical 5V digital logic systems.

Q: Can these parts be used interchangeably in high-speed applications?

A: Yes, within the specified operating parameters. The SN74LS27N provides faster propagation delay, making it suitable for timing-critical applications. Both parts meet the 0°C to 70°C operating temperature range for industrial and commercial use.