LM3671MF-1.5 Equivalent & Substitute Parts

Part Overview

The LM3671MF-1.5 is a buck switching regulator IC from Texas Instruments, designed for positive fixed 1.5V output applications with 600mA current capacity. This component operates across a 2.7V to 5.5V input range with a 2MHz switching frequency and integrated synchronous rectification. The part is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production requirements. Active alternatives from Texas Instruments, Analog Devices, and Microchip Technology provide direct functional replacement with enhanced product status and compliance certifications.

Substiute Parts

LM3671MF-1.5

Texas InstrumentsIn Stock: 7920LM3671MF-1.5 Datasheet

Current PartRFQ

LM3671MF-1.5/NOPB

Texas InstrumentsIn Stock: 2164LM3671MF-1.5/NOPB Datasheet

DirectRFQ

LM3674MF-1.5/NOPB

Texas InstrumentsIn Stock: 1128LM3674MF-1.5/NOPB Datasheet

DirectRFQ

ADP2108AUJZ-1.5-R7

Analog Devices Inc.In Stock: 3539ADP2108AUJZ-1.5-R7 Datasheet

MFR RecommendedRFQ

MCP1603T-150I/OS

Microchip TechnologyIn Stock: 1136MCP1603T-150I/OS Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the LM3671MF-1.5 is determined by the following critical parameters:

Primary Substitution Criteria:

• Output voltage: Fixed 1.5V
• Output current: Minimum 600mA (or 500mA for reduced-current applications)
• Input voltage range: 2.7V to 5.5V minimum compatibility
• Topology: Buck switching regulator with synchronous rectification
• Package: SOT-23-5 or TSOT-23-5 (pin-compatible surface mount)
• Switching frequency: 2MHz or higher acceptable

Compliance Considerations:

• RoHS3 compliance required for new designs
• Moisture sensitivity level: MSL 1 (Unlimited)
• Operating temperature range: -40°C minimum, 85°C or higher maximum

Substitute parts are grouped into two categories: direct Texas Instruments equivalents (LM3671MF-1.5/NOPB, LM3674MF-1.5/NOPB) and cross-manufacturer alternatives (ADP2108AUJZ-1.5-R7 from Analog Devices, MCP1603T-150I/OS from Microchip Technology). All listed substitutes maintain the core electrical specifications while offering improved product status and regulatory compliance.

Parameter Comparison

Engineering Selection Recommendations

Direct Texas Instruments Equivalents:

LM3671MF-1.5/NOPB is the primary recommended substitute. This part maintains identical electrical specifications and package configuration while offering active product status and RoHS3 compliance. The NOPB designation indicates lead-free construction, meeting modern regulatory requirements. With 2100 units in stock, this option provides immediate availability for production requirements.

LM3674MF-1.5/NOPB serves as an alternative Texas Instruments solution with matching electrical performance. The extended operating temperature range (-30°C to 85°C) is narrower than the original part but remains suitable for most industrial applications. This variant is available in Tape & Reel packaging with 1101 units in stock.

Cross-Manufacturer Alternatives:

ADP2108AUJZ-1.5-R7 from Analog Devices provides enhanced specifications including a lower minimum input voltage (2.3V versus 2.7V) and extended operating temperature range (-40°C to 125°C). The 3MHz switching frequency enables smaller external component sizing. This part is RoHS3 compliant and actively supported, with 3458 units available.

MCP1603T-150I/OS from Microchip Technology offers a reduced output current specification (500mA versus 600mA) but maintains all other critical parameters. The extended temperature range (-40°C to 125°C) and RoHS3 compliance make this suitable for demanding environments. Selection of this part requires confirmation that the 500mA output current meets application requirements.

Compliance and Availability:

All substitute parts carry RoHS3 compliance and REACH Unaffected status, meeting current regulatory standards. The original LM3671MF-1.5 is RoHS non-compliant and obsolete, making transition to an active substitute necessary for new designs and long-term production support.

Frequently Asked Questions (FAQ)

Q: Can LM3671MF-1.5/NOPB directly replace the obsolete LM3671MF-1.5?

A: Yes. LM3671MF-1.5/NOPB is electrically and mechanically identical to the original part. Both operate at 1.5V fixed output, 600mA current, 2.7V to 5.5V input range, and use the same SOT-23-5 package. The primary difference is product status (active versus obsolete) and RoHS compliance (RoHS3 versus non-compliant). Pin-for-pin substitution is direct.

Q: What is the difference between LM3671MF-1.5/NOPB and LM3674MF-1.5/NOPB?

A: Both parts share identical electrical specifications and package type. The LM3674 variant has a narrower operating temperature range (-30°C to 85°C versus -40°C to 85°C). Selection depends on application temperature requirements. For standard industrial applications within -30°C to 85°C, either part is acceptable.

Q: Can ADP2108AUJZ-1.5-R7 be used as a substitute?

A: Yes, with design considerations. The ADP2108 maintains 1.5V output and 600mA current but operates at 3MHz switching frequency (versus 2MHz). The lower minimum input voltage (2.3V) and extended temperature range (-40°C to 125°C) provide additional design flexibility. PCB layout and external component values may require adjustment due to the higher switching frequency.

Q: Is MCP1603T-150I/OS suitable for applications requiring 600mA output?

A: MCP1603T-150I/OS provides only 500mA output current. This part is suitable only for applications where the load current does not exceed 500mA. For designs requiring the full 600mA specification, use LM3671MF-1.5/NOPB, LM3674MF-1.5/NOPB, or ADP2108AUJZ-1.5-R7.

Q: Are all substitute parts available in the same package?

A: LM3671MF-1.5/NOPB and LM3674MF-1.5/NOPB use SC-74A, SOT-753 packaging. ADP2108AUJZ-1.5-R7 and MCP1603T-150I/OS use SOT-23-5 Thin (TSOT-23-5) packaging. Both package types are pin-compatible SOT-23-5 variants suitable for surface mount assembly. Verify PCB footprint compatibility before design implementation.

Q: What is the significance of the NOPB designation?

A: NOPB indicates "No Plumbum" (lead-free) construction, meeting RoHS compliance requirements. This designation confirms the part uses lead-free solder and materials, essential for modern electronics manufacturing and regulatory compliance.

Q: Which substitute offers the best temperature performance?

A: ADP2108AUJZ-1.5-R7 and MCP1603T-150I/OS both support -40°C to 125°C operating range, compared to -40°C to 85°C for the original and LM3671MF-1.5/NOPB. For applications requiring extended temperature operation, these cross-manufacturer alternatives provide superior thermal performance.