LM3671MF-1.2 Buck Switching Regulator Equivalent & Substitute Parts

Part Overview

The LM3671MF-1.2 is a buck switching regulator IC manufactured by Texas Instruments, delivering a fixed 1.2V output at 600mA with a 2MHz switching frequency. This device operates across a 2.7V to 5.5V input range and features synchronous rectification in a compact SC-74A (SOT-753) surface mount package. The part is currently in Last Time Buy status, making identification of active equivalent and substitute components essential for ongoing design support and procurement planning.

Substiute Parts

LM3671MF-1.2

Texas InstrumentsIn Stock: 9504LM3671MF-1.2 Datasheet

Current PartRFQ

LM3674MF-1.2/NOPB

Texas InstrumentsIn Stock: 1147LM3674MF-1.2/NOPB Datasheet

DirectRFQ

LM3674MFX-1.2/NOPB

Texas InstrumentsIn Stock: 4445LM3674MFX-1.2/NOPB Datasheet

DirectRFQ

LM3671MF-1.2/NOPB

Texas InstrumentsIn Stock: 37997LM3671MF-1.2/NOPB Datasheet

MFR RecommendedRFQ

ADP2108AUJZ-1.2-R7

Analog Devices Inc.In Stock: 18099ADP2108AUJZ-1.2-R7 Datasheet

MFR RecommendedRFQ

SC4626CSKTRT

Semtech CorporationIn Stock: 9297SC4626CSKTRT Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the LM3671MF-1.2 is determined by the following critical parameters:

• Output voltage: 1.2V fixed
• Output current capability: minimum 600mA
• Input voltage range: 2.7V to 5.5V minimum compatibility
• Topology: Buck (step-down) switching regulator
• Package: SC-74A or SOT-23-5 compatible footprint
• Synchronous rectification: required
• RoHS3 compliance: required

Substitute parts must maintain electrical compatibility across these parameters. Variations in switching frequency, operating temperature range, and current capacity above the minimum threshold do not preclude substitution when other parameters align.

Parameter Comparison

Engineering Selection Recommendations

Primary Recommendation: LM3671MF-1.2/NOPB

This manufacturer-recommended part is the direct equivalent with identical electrical specifications and operating temperature range (-40°C to 85°C). Active product status ensures long-term availability and supply chain stability. ROHS3 compliance and unlimited moisture sensitivity level (MSL 1) support standard manufacturing processes.

Secondary Recommendation: LM3674MF-1.2/NOPB or LM3674MFX-1.2/NOPB

Both LM3674 variants are active Texas Instruments products with identical electrical performance. The LM3674MF-1.2/NOPB is available in Cut Tape packaging, while LM3674MFX-1.2/NOPB is supplied on Tape & Reel. Operating temperature range is -30°C to 85°C, which is acceptable for applications not requiring the full -40°C lower limit. Both maintain ROHS3 compliance and identical package footprint compatibility.

Alternative Recommendation: ADP2108AUJZ-1.2-R7

The Analog Devices ADP2108AUJZ-1.2-R7 provides equivalent 1.2V, 600mA output with extended operating temperature range (-40°C to 125°C). Input voltage minimum is 2.3V, providing lower input threshold capability. Switching frequency is 3MHz. Package is SOT-23-5 Thin (TSOT-23-5), which is footprint-compatible with SC-74A. ROHS3 compliance is maintained. This option is suitable for designs requiring higher temperature operation or lower input voltage thresholds.

Not Recommended for New Designs: SC4626CSKTRT

The Semtech SC4626CSKTRT is marked "Not For New Designs" and should not be selected for new development. While it provides 1A output current (exceeding the 600mA requirement) and extended temperature range (-40°C to 125°C), its obsolescence status makes it unsuitable for long-term product support.

Frequently Asked Questions (FAQ)

Q: Can I use LM3674MF-1.2/NOPB as a direct replacement for LM3671MF-1.2?

A: Yes. Both parts deliver 1.2V at 600mA with identical switching frequency (2MHz), input voltage range (2.7V to 5.5V), and package (SC-74A, SOT-753). The operating temperature range differs by 10°C at the lower limit (-30°C vs -40°C). If your application operates above -30°C, this substitution is fully compatible.

Q: What is the difference between LM3674MF-1.2/NOPB and LM3674MFX-1.2/NOPB?

A: Both parts are electrically identical. The difference is packaging format: LM3674MF-1.2/NOPB is supplied in Cut Tape (CT) & Digi-Reel format, while LM3674MFX-1.2/NOPB is supplied on Tape & Reel (TR). Select based on your procurement and assembly requirements.

Q: Can I substitute the ADP2108AUJZ-1.2-R7 for the LM3671MF-1.2?

A: Yes, with design verification. The ADP2108AUJZ-1.2-R7 maintains the same 1.2V output and 600mA current rating. Key differences are switching frequency (3MHz vs 2MHz) and operating temperature range (-40°C to 125°C vs -40°C to 85°C). The TSOT-23-5 package is footprint-compatible with SC-74A. Verify that the higher switching frequency does not introduce EMI or thermal concerns in your specific application.

Q: Why is SC4626CSKTRT not recommended?

A: The SC4626CSKTRT carries a "Not For New Designs" status, indicating Semtech has discontinued active support for this product line. While it meets the electrical requirements (1.2V, 1A output), its obsolescence status creates supply chain risk and limits access to technical support and future revisions.

Q: What packaging considerations apply to these substitutes?

A: All recommended substitutes use SC-74A or SOT-23-5 compatible packages with identical pin configurations. The ADP2108AUJZ-1.2-R7 uses a Thin SOT-23-5 (TSOT-23-5) variant, which maintains footprint compatibility but may have slightly different height specifications. Verify PCB assembly equipment compatibility if height-constrained applications are involved.

Q: Are all recommended substitutes RoHS3 compliant?

A: Yes. LM3671MF-1.2/NOPB, LM3674MF-1.2/NOPB, LM3674MFX-1.2/NOPB, and ADP2108AUJZ-1.2-R7 are all ROHS3 compliant. SC4626CSKTRT is RoHS compliant but not specifically ROHS3 certified.