LM3670MF-1.5 Equivalent & Substitute Parts

Part Overview

The LM3670MF-1.5 is a buck switching regulator IC from Texas Instruments designed for positive fixed 1.5V output applications with 350mA current capacity. This device operates in the 2.5V to 5.5V input range and features a 1MHz switching frequency with integrated synchronous rectification. The part is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production requirements.

Substiute Parts

LM3670MF-1.5

Texas InstrumentsIn Stock: 2116LM3670MF-1.5 Datasheet

Current PartRFQ

LM3670MF-1.5/NOPB

Texas InstrumentsIn Stock: 3824LM3670MF-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

RT8009-15GJ5

Richtek USA Inc.In Stock: 1074RT8009-15GJ5 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the LM3670MF-1.5 is determined by the following critical parameters:

• Output Voltage: Must be fixed at 1.5V
• Topology: Buck (step-down) switching regulator
• Output Configuration: Positive
• Package Type: SOT-23-5 form factor (physical and electrical compatibility)
• Synchronous Rectification: Required
• Input Voltage Range: Minimum 2.5V to 5.5V maximum
• Output Current Capability: Minimum 350mA (equal or greater)

Substitute parts are grouped into two categories:

1. Direct Equivalent: LM3670MF-1.5/NOPB (same manufacturer, identical electrical specifications, active product status)
2. Functional Equivalents: ADP2108AUJZ-1.5-R7, MCP1603T-150I/OS, and RT8009-15GJ5 (meet or exceed all critical parameters, active product status, RoHS3 compliant)

Parameter Comparison

Engineering Selection Recommendations

LM3670MF-1.5/NOPB is the primary substitute for direct replacement. It maintains identical electrical specifications and package form factor while offering active product status and ROHS3 compliance. This part is recommended for designs requiring minimal validation effort and maximum compatibility with existing layouts.

ADP2108AUJZ-1.5-R7 provides enhanced output current capability (600mA versus 350mA) and extended operating temperature range (-40°C to 125°C). The higher switching frequency (3MHz) enables smaller external component sizing. ROHS3 compliance and active product status support long-term supply chain stability.

MCP1603T-150I/OS offers 500mA output current and extended temperature range (-40°C to 125°C). The 2MHz switching frequency provides a balance between component size and efficiency. ROHS3 compliance and active status ensure regulatory compliance and availability.

RT8009-15GJ5 delivers 600mA output current with switching frequency of 1.25MHz, closest to the original 1MHz specification. ROHS3 compliance and active product status are confirmed. Moisture sensitivity level (MSL 3) requires controlled storage conditions compared to MSL 1 for other substitutes.

All substitute parts meet or exceed the critical electrical parameters of the LM3670MF-1.5 and are available in compatible SOT-23-5 package variants.

Frequently Asked Questions (FAQ)

Q: Can LM3670MF-1.5/NOPB be used as a direct drop-in replacement?

A: Yes. LM3670MF-1.5/NOPB is electrically and mechanically identical to LM3670MF-1.5, with the same output voltage (1.5V), current rating (350mA), input range (2.5V to 5.5V), and SOT-23-5 package. The primary difference is active product status and ROHS3 compliance.

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

A: Both are physically compatible SOT-23-5 form factors. TSOT-23-5 denotes a thin variant with identical pin configuration and electrical performance. Designs using standard SOT-23-5 can accommodate TSOT-23-5 devices without layout modification.

Q: Why do some substitutes have higher output current ratings?

A: ADP2108AUJZ-1.5-R7, MCP1603T-150I/OS, and RT8009-15GJ5 are rated for 500mA to 600mA output current, exceeding the original 350mA specification. These parts are functionally compatible and provide design margin for applications requiring higher current delivery or future design iterations.

Q: Are all substitute parts RoHS compliant?

A: LM3670MF-1.5/NOPB, ADP2108AUJZ-1.5-R7, MCP1603T-150I/OS, and RT8009-15GJ5 are all ROHS3 compliant. The original LM3670MF-1.5 is RoHS non-compliant, making compliant substitutes necessary for regulated applications.

Q: What is the significance of operating temperature range differences?

A: The original LM3670MF-1.5 operates from -40°C to 85°C. ADP2108AUJZ-1.5-R7 and MCP1603T-150I/OS extend this to -40°C to 125°C, providing thermal margin for high-temperature applications. RT8009-15GJ5 maintains the -40°C to 85°C range.

Q: How do switching frequency differences affect circuit design?

A: The original operates at 1MHz. Substitutes range from 1.25MHz to 3MHz. Higher switching frequencies enable smaller external inductors and capacitors but may increase switching losses. RT8009-15GJ5 (1.25MHz) provides the closest frequency match for minimal design changes.

Q: What is the moisture sensitivity level (MSL) and why does it matter?

A: MSL indicates storage and handling requirements. LM3670MF-1.5/NOPB, ADP2108AUJZ-1.5-R7, and MCP1603T-150I/OS are MSL 1 (unlimited shelf life). RT8009-15GJ5 is MSL 3 (168-hour floor life after moisture exposure), requiring controlled storage conditions and bake-out procedures before reflow soldering.