LM2678SX-3.3 Equivalent & Substitute Parts

Part Overview

The LM2678SX-3.3 is a buck switching regulator IC from Texas Instruments' SIMPLE SWITCHER® series, designed for step-down voltage conversion with a fixed 3.3V output at 5A maximum current. This device operates across an input voltage range of 8V to 40V with a switching frequency of 260kHz and is housed in a TO-263-8 (D2PAK) surface mount package.

The LM2678SX-3.3 is classified as obsolete. Identifying equivalent substitute parts is necessary to ensure design continuity, maintain supply chain reliability, and support ongoing production or maintenance requirements for systems utilizing this regulator.

Substiute Parts

LM2678SX-3.3

Texas InstrumentsIn Stock: 3381LM2678SX-3.3 Datasheet

Current PartRFQ

LM2678SX-3.3/NOPB

Texas InstrumentsIn Stock: 1716LM2678SX-3.3/NOPB Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the LM2678SX-3.3 is determined by strict equivalence across the following parameters:

• Output voltage specification (3.3V fixed)
• Maximum output current rating (5A)
• Input voltage operating range (8V to 40V minimum/maximum)
• Switching topology and frequency (Buck, 260kHz)
• Package and pinout compatibility (TO-263-8, D2PAK)
• Operating temperature range (-40°C to 125°C)

The LM2678SX-3.3/NOPB qualifies as a direct substitute based on identical electrical specifications and package configuration. The primary distinction is product status and compliance certification.

Parameter Comparison

Engineering Selection Recommendations

The LM2678SX-3.3/NOPB is the direct functional equivalent of the LM2678SX-3.3. Both devices share identical electrical characteristics, output specifications, and package configuration, ensuring pin-for-pin and functional compatibility.

The LM2678SX-3.3/NOPB is recommended for new designs and ongoing production due to its active product status. This part maintains full availability through standard distribution channels and is supported by current technical documentation.

For legacy systems currently using the obsolete LM2678SX-3.3, the LM2678SX-3.3/NOPB provides seamless substitution without circuit modification. The ROHS3 compliance of the substitute part aligns with modern manufacturing and environmental standards, whereas the original part carries non-compliant status.

Frequently Asked Questions (FAQ)

Q: Are the LM2678SX-3.3 and LM2678SX-3.3/NOPB electrically identical?

A: Yes. Both parts deliver identical electrical performance across all specified parameters: 3.3V fixed output, 5A maximum current, 8V to 40V input range, 260kHz switching frequency, and -40°C to 125°C operating temperature range.

Q: Can the LM2678SX-3.3/NOPB be used as a direct replacement in existing designs?

A: Yes. The LM2678SX-3.3/NOPB is pin-for-pin compatible and functionally equivalent. No circuit redesign or PCB modification is required for substitution.

Q: What does the "/NOPB" suffix indicate?

A: The "/NOPB" designation indicates the part is supplied without plumbum (lead-free), reflecting RoHS3 compliance and modern packaging standards.

Q: Why is the original LM2678SX-3.3 marked as obsolete?

A: Product obsolescence typically reflects manufacturer discontinuation decisions. The LM2678SX-3.3/NOPB remains in active production and is the recommended path for continued supply.

Q: Are there packaging differences between these parts?

A: Both parts use the TO-263-8 (D2PAK) package. The LM2678SX-3.3/NOPB is available in Cut Tape (CT) and Digi-Reel® formats, supporting automated assembly processes.

Q: What compliance certifications apply to each part?

A: The LM2678SX-3.3 is RoHS non-compliant. The LM2678SX-3.3/NOPB is ROHS3 compliant and REACH unaffected. Both carry EAR99 export classification.