LM3485MM Buck Regulator Controller IC Equivalent & Substitute Parts

Part Overview

The LM3485MM is a buck regulator positive output step-down DC-DC controller IC manufactured by Texas Instruments in 8-VSSOP packaging. This device functions as a transistor driver for step-down topology applications with a single output phase and 100% maximum duty cycle. The main part is classified as "Not For New Designs," which necessitates identification of active equivalent alternatives that maintain electrical and mechanical compatibility while offering current product status and improved compliance certifications.

Key Parameters

Parameter	Value
Manufacturer	Texas Instruments
Category	Power Management (PMIC)
Function	Step-Down (Buck)
Output Type	Transistor Driver
Output Configuration	Positive
Number of Outputs	1
Output Phases	1
Voltage Supply Range (Vcc/Vdd)	4.5V ~ 35V
Duty Cycle (Max)	100%
Synchronous Rectifier	No
Clock Sync	No
Operating Temperature Range	-40°C ~ 125°C (TJ)
Mounting Type	Surface Mount
Package / Case	8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
Supplier Device Package	8-VSSOP
Moisture Sensitivity Level (MSL)	1 (Unlimited)
REACH Status	REACH Unaffected
ECCN	EAR99

Substitute Part Grouping Explanation

Substitution of the LM3485MM is determined by strict equivalence across the following electrical and mechanical parameters:

Topology & Function: Buck regulator controller with step-down output configuration
Output Characteristics: Single output, positive configuration, transistor driver output type
Electrical Specifications: 4.5V ~ 35V supply voltage range, 100% maximum duty cycle, -40°C ~ 125°C operating temperature
Package Compatibility: 8-VSSOP package with 8-TSSOP/8-MSOP physical dimensions (0.118", 3.00mm width)
Environmental Compliance: MSL 1, REACH Unaffected, EAR99 classification

Substitute parts are grouped into two categories:

Direct Manufacturer Equivalents (LM3485 Base Series): Parts maintaining identical base product number with enhanced packaging and compliance certifications (LM3485MM/NOPB, LM3485MMX/NOPB, LM3485Q1MM/NOPB).

Parametric Equivalents (LM3489 Base Series): Parts with identical electrical specifications and package form factor but different base product designation, offering enhanced control features (Current Limit, Enable) and automotive-grade qualification (LM3489MM, LM3489MM/NOPB, LM3489MMX/NOPB, LM3489QMM/NOPB, LM3489QMMX/NOPB).

Parameter Comparison

Part Number	Manufacturer	Base Product	Voltage Supply	Duty Cycle Max	Operating Temp	Package	Switching Freq	Control Features	Product Status	RoHS Status	Grade	Qualification	Inventory (Pcs)
LM3485MM	Texas Instruments	LM3485	4.5V ~ 35V	100%	-40°C ~ 125°C	8-VSSOP	—	—	Not For New Designs	RoHS non-compliant	—	—	4957
LM3485MM/NOPB	Texas Instruments	LM3485	4.5V ~ 35V	100%	-40°C ~ 125°C	8-VSSOP	—	—	Active	ROHS3 Compliant	—	—	96400
LM3485MMX/NOPB	Texas Instruments	LM3485	4.5V ~ 35V	100%	-40°C ~ 125°C	8-VSSOP	—	—	Active	ROHS3 Compliant	—	—	55100
LM3485Q1MM/NOPB	Texas Instruments	LM3485	4.5V ~ 35V	100%	-40°C ~ 125°C	8-VSSOP	—	—	Active	ROHS3 Compliant	Automotive	AEC-Q100	2140
LM3489MM	Texas Instruments	LM3489	4.5V ~ 35V	100%	-40°C ~ 125°C	8-VSSOP	Up to 1MHz	Current Limit, Enable	Last Time Buy	ROHS3 Compliant	Automotive	AEC-Q100	2300
LM3489MM/NOPB	Texas Instruments	LM3489	4.5V ~ 35V	100%	-40°C ~ 125°C	8-VSSOP	Up to 1MHz	Current Limit, Enable	Active	ROHS3 Compliant	Automotive	AEC-Q100	15700
LM3489MMX/NOPB	Texas Instruments	LM3489	4.5V ~ 35V	100%	-40°C ~ 125°C	8-VSSOP	Up to 1MHz	Current Limit, Enable	Active	ROHS3 Compliant	Automotive	AEC-Q100	16371
LM3489QMM/NOPB	Texas Instruments	LM3489	4.5V ~ 35V	100%	-40°C ~ 125°C	8-VSSOP	Up to 1MHz	Current Limit, Enable	Active	ROHS3 Compliant	Automotive	AEC-Q100	10684
LM3489QMMX/NOPB	Texas Instruments	LM3489	4.5V ~ 35V	100%	-40°C ~ 125°C	8-VSSOP	Up to 1MHz	Current Limit, Enable	Active	ROHS3 Compliant	Automotive	AEC-Q100	3060

Engineering Selection Recommendations

For Direct LM3485 Series Replacement: LM3485MM/NOPB is the primary direct equivalent, offering Active product status, ROHS3 compliance, and highest inventory availability (96,400 pcs). LM3485MMX/NOPB provides identical electrical and mechanical specifications with extended temperature range qualification. LM3485Q1MM/NOPB adds automotive-grade qualification (AEC-Q100) for applications requiring automotive compliance.

For Enhanced Functionality with LM3489 Series: LM3489MM/NOPB is recommended for new designs requiring Active product status with integrated Current Limit and Enable control features. LM3489MMX/NOPB and LM3489QMMX/NOPB provide equivalent functionality with automotive qualification. All LM3489 variants maintain identical electrical specifications (4.5V ~ 35V supply, 100% duty cycle, -40°C ~ 125°C operation) and package compatibility while offering switching frequency specification (up to 1MHz) and enhanced control capabilities.

Compliance Considerations: All substitute parts except the original LM3485MM achieve ROHS3 compliance. Automotive applications should prioritize LM3485Q1MM/NOPB or any LM3489 variant carrying AEC-Q100 qualification.

Frequently Asked Questions (FAQ)

Q: Can LM3485MM/NOPB directly replace LM3485MM? A: Yes. Both parts share identical electrical specifications (4.5V ~ 35V supply, 100% duty cycle, -40°C ~ 125°C operation) and 8-VSSOP package form factor. The primary differences are product status (Active vs. Not For New Designs) and RoHS compliance (ROHS3 vs. non-compliant). LM3485MM/NOPB is the recommended direct replacement.

Q: What is the difference between LM3485 and LM3489 series? A: Both series maintain identical core electrical specifications and package compatibility. The LM3489 series adds integrated control features (Current Limit, Enable) and specifies switching frequency capability (up to 1MHz). LM3489 variants carry automotive-grade qualification (AEC-Q100) and Active product status, making them suitable for new designs and automotive applications.

Q: Are all substitute parts pin-compatible? A: Yes. All listed substitutes use the 8-VSSOP package with identical 8-TSSOP/8-MSOP physical dimensions (0.118", 3.00mm width), ensuring mechanical and electrical pin compatibility.

Q: Which part should I select for new automotive designs? A: LM3485Q1MM/NOPB (LM3485 series with AEC-Q100) or any LM3489 variant (LM3489MM/NOPB, LM3489MMX/NOPB, LM3489QMM/NOPB, LM3489QMMX/NOPB) are qualified for automotive applications. LM3489 variants offer additional control features and higher inventory availability.

Q: What does "Last Time Buy" status mean for LM3489MM? A: Last Time Buy indicates the part is in final production phase with limited future availability. For long-term supply assurance, select Active status parts: LM3489MM/NOPB, LM3489MMX/NOPB, LM3489QMM/NOPB, or LM3489QMMX/NOPB.

Q: Are there packaging differences between substitute parts? A: All parts use 8-VSSOP supplier device package. Packaging options vary between Cut Tape (CT) & Digi-Reel® and Tape & Reel (TR) formats, but these are supply chain variations that do not affect electrical or mechanical compatibility.

Q: What is the significance of the "/NOPB" suffix? A: The "/NOPB" suffix indicates "No Plumbum" (lead-free) packaging, confirming RoHS compliance. Parts without this suffix may contain lead and are typically non-compliant with modern environmental regulations.

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