SN74LS279AD Equivalent & Substitute Parts

Part Overview

The SN74LS279AD is a quad S-R latch logic integrated circuit manufactured by Texas Instruments, housed in a 16-SOIC surface mount package. This component functions as a 4-channel set-reset latch with standard output configuration, operating within the 4.75V to 5.25V supply voltage range. The device is classified as Last Time Buy, indicating discontinued production status. Identifying equivalent substitute parts is necessary to ensure design continuity and maintain component availability for new production runs and field replacements.

Substiute Parts

SN74LS279AD

Texas InstrumentsIn Stock: 1047SN74LS279AD Datasheet

Current PartRFQ

SN74LS279ADR

Texas InstrumentsIn Stock: 5898SN74LS279ADR Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SN74LS279AD is determined by strict equivalence across the following critical parameters:

• Logic Type: S-R Latch configuration with 4 independent channels
• Circuit Ratio: 1:1 channel configuration
• Output Type: Standard output
• Package / Case: 16-SOIC form factor with identical pin pitch and dimensions
• Voltage - Supply: 4.75V ~ 5.25V operating range
• Delay Time - Propagation: 12ns maximum
• Current - Output High, Low: 400µA and 8mA specifications
• Operating Temperature: 0°C ~ 70°C range
• Mounting Type: Surface mount technology

The substitute part SN74LS279ADR meets all these criteria while offering improved product status and availability.

Parameter Comparison

Engineering Selection Recommendations

The SN74LS279ADR is the direct functional equivalent of the SN74LS279AD. Both devices share identical electrical specifications, pin configuration, and package dimensions. The primary distinction is product lifecycle status: the SN74LS279AD is Last Time Buy, while the SN74LS279ADR maintains Active status with significantly higher inventory availability (5835 units versus 981 units).

For new designs and production requirements, the SN74LS279ADR is the appropriate selection. Both parts maintain ROHS3 compliance and REACH unaffected status, satisfying regulatory requirements. The packaging difference (Tube versus Cut Tape & Digi-Reel) does not affect electrical performance and reflects standard distribution formats for active versus discontinued product lines.

Frequently Asked Questions (FAQ)

Q: Can SN74LS279ADR directly replace SN74LS279AD in existing designs?

A: Yes. The SN74LS279ADR is electrically and mechanically identical to the SN74LS279AD. Pin configuration, package dimensions, and all electrical parameters are equivalent. Direct substitution is valid without circuit modification.

Q: What is the difference between Tube and Cut Tape packaging?

A: Tube packaging is standard for Last Time Buy products, while Cut Tape & Digi-Reel packaging is standard for active production. Both formats contain identical components. The packaging format does not affect component performance or compatibility.

Q: Are there any compliance differences between these parts?

A: No. Both the SN74LS279AD and SN74LS279ADR maintain identical RoHS3 compliance, REACH unaffected status, and Moisture Sensitivity Level 1 (Unlimited) ratings.

Q: Why is inventory availability different between these parts?

A: The SN74LS279AD is Last Time Buy status with limited remaining stock (981 units). The SN74LS279ADR is Active status with ongoing production and higher inventory (5835 units). This reflects standard lifecycle management practices.

Q: Are the propagation delay and output current specifications identical?

A: Yes. Both parts specify 12ns propagation delay and 400µA / 8mA output current (high/low). All timing and drive characteristics are equivalent.