LM3671MF-3.3 Equivalent & Substitute Parts

Part Overview

The LM3671MF-3.3 is a buck switching regulator IC from Texas Instruments designed for positive fixed 3.3V output applications with 600mA current capacity. This device operates in the 2.7V to 5.5V input voltage range and features a 2MHz switching frequency with integrated synchronous rectification. The part is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production support.

Substiute Parts

LM3671MF-3.3

Texas InstrumentsIn Stock: 1490LM3671MF-3.3 Datasheet

Current PartRFQ

LM3671MF-3.3/NOPB

Texas InstrumentsIn Stock: 60471LM3671MF-3.3/NOPB Datasheet

DirectRFQ

ADP2108AUJZ-3.3-R7

Analog Devices Inc.In Stock: 12307ADP2108AUJZ-3.3-R7 Datasheet

MFR RecommendedRFQ

MCP1603T-330I/OS

Microchip TechnologyIn Stock: 34964MCP1603T-330I/OS Datasheet

MFR RecommendedRFQ

SC4626ZSKTRT

SemtechIn Stock: 9235SC4626ZSKTRT Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the LM3671MF-3.3 is determined by the following core parameters:

• Output voltage: 3.3V fixed
• Output topology: Buck (step-down)
• Output configuration: Positive
• Number of outputs: Single output
• Package compatibility: SOT-23-5 form factor
• Synchronous rectification capability: Required
• Input voltage range: Minimum 2.7V, maximum 5.5V
• Mounting type: Surface mount

Substitute parts must maintain compatibility across these parameters. Variations in switching frequency, output current capacity, and operating temperature range are permissible provided the substitute meets or exceeds the original specifications for the intended application.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitute: LM3671MF-3.3/NOPB

The LM3671MF-3.3/NOPB is the direct equivalent from Texas Instruments with identical electrical specifications and package format. This part is active in production status and ROHS3 compliant, making it the preferred choice for direct replacement in new designs and production continuity.

Secondary Substitute: ADP2108AUJZ-3.3-R7

The ADP2108AUJZ-3.3-R7 from Analog Devices Inc. provides equivalent functionality with extended input voltage range (2.3V minimum) and higher operating temperature range (-40°C to 125°C). The TSOT-23-5 package is physically compatible with SOT-23-5 footprints. This part is active and ROHS3 compliant.

Secondary Substitute: MCP1603T-330I/OS

The MCP1603T-330I/OS from Microchip Technology meets core substitution criteria with matching input voltage range and switching frequency. Output current is rated at 500mA, which is lower than the original 600mA specification. This part is active and ROHS3 compliant with extended operating temperature range (-40°C to 125°C).

Tertiary Substitute: SC4626ZSKTRT

The SC4626ZSKTRT from Semtech provides higher output current capacity (1A) and extended operating temperature range (-40°C to 125°C). This part is classified as not for new designs, limiting its suitability for forward-looking applications. RoHS compliance is confirmed.

Frequently Asked Questions (FAQ)

Q: Can LM3671MF-3.3/NOPB be used as a direct replacement for LM3671MF-3.3?

A: Yes. The LM3671MF-3.3/NOPB is the active production equivalent with identical electrical specifications, package format, and pinout. The primary difference is product status (active vs. obsolete) and RoHS compliance (ROHS3 vs. non-compliant).

Q: What is the difference between SOT-23-5 and TSOT-23-5 packages?

A: TSOT-23-5 is a thin variant of the SOT-23-5 package with reduced height. Both packages share the same footprint and pinout, making them mechanically and electrically compatible for PCB assembly purposes.

Q: Is MCP1603T-330I/OS suitable if my application requires 600mA output current?

A: The MCP1603T-330I/OS is rated for 500mA maximum output current, which is below the original 600mA specification. This part is suitable only for applications with output current requirements not exceeding 500mA.

Q: Why is SC4626ZSKTRT marked as not for new designs?

A: The SC4626ZSKTRT carries a "Not For New Designs" status from the manufacturer, indicating the part is in mature or declining production phase. While functionally compatible, it is not recommended for new product development or long-term production commitments.

Q: What are the key parameters that determine substitution compatibility?

A: Substitution compatibility is determined by output voltage (3.3V fixed), buck topology, positive output configuration, single output, SOT-23-5 package compatibility, synchronous rectification capability, input voltage range (2.7V to 5.5V minimum/maximum), and surface mount mounting type.

Q: Are all substitute parts RoHS compliant?

A: LM3671MF-3.3/NOPB, ADP2108AUJZ-3.3-R7, and MCP1603T-330I/OS are ROHS3 compliant. SC4626ZSKTRT is RoHS compliant. The original LM3671MF-3.3 is RoHS non-compliant.