LM3485MMX Equivalent & Substitute Parts

Part Overview

The LM3485MMX 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 number LM3485MMX is classified as obsolete, which necessitates identification of active equivalent and substitute parts for ongoing design and procurement requirements. Substitute parts must maintain identical electrical and mechanical parameters to ensure direct compatibility in existing circuit designs.

Key Parameters

Parameter	Specification
Manufacturer	Texas Instruments
Category	Power Management (PMIC)
Function	Step-Down DC-DC Controller
Output Type	Transistor Driver
Output Configuration	Positive
Topology	Buck
Number of Outputs	1
Output Phases	1
Voltage Supply Range (Vcc/Vdd)	4.5V ~ 35V
Duty Cycle (Max)	100%
Operating Temperature	-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
Synchronous Rectifier	No
Clock Sync	No
Moisture Sensitivity Level (MSL)	1 (Unlimited)
REACH Status	REACH Unaffected
ECCN	EAR99

Substitute Part Grouping Explanation

Substitution of the obsolete LM3485MMX is determined by strict equivalence across the following critical parameters:

Electrical Parameters: Voltage supply range (4.5V ~ 35V), output configuration (positive), topology (buck), number of outputs (1), output phases (1), duty cycle maximum (100%), and operating temperature range (-40°C ~ 125°C).

Mechanical Parameters: Package type (8-TSSOP, 8-MSOP with 0.118" / 3.00mm width), mounting type (surface mount), and supplier device package (8-VSSOP).

Functional Parameters: Output type (transistor driver), function (step-down), and absence of synchronous rectifier and clock sync features.

Substitute parts are grouped into two categories:

Direct Manufacturer Equivalents (LM3485 Base Series): LM3485MMX/NOPB and LM3485MM/NOPB maintain identical electrical and mechanical specifications with active product status and RoHS3 compliance.

Parametric Equivalents (LM3489 Base Series): LM3489MM, LM3489MM/NOPB, LM3489MMX/NOPB, LM3489QMM/NOPB, and LM3489QMMX/NOPB provide full parameter equivalence with additional control features (current limit, enable) and switching frequency specification (up to 1MHz). The LM3485Q1MM/NOPB variant includes automotive-grade qualification (AEC-Q100).

All substitute parts share identical package, voltage supply range, duty cycle, operating temperature, and output configuration with the main part.

Parameter Comparison

Part Number	Manufacturer	Product Status	Voltage Supply (Vcc/Vdd)	Duty Cycle (Max)	Operating Temp	Package	RoHS Status	Inventory (Pcs)	Control Features	Automotive Grade
LM3485MMX	Texas Instruments	Obsolete	4.5V ~ 35V	100%	-40°C ~ 125°C	8-VSSOP	RoHS Non-Compliant	30314	—	No
LM3485MMX/NOPB	Texas Instruments	Active	4.5V ~ 35V	100%	-40°C ~ 125°C	8-VSSOP	RoHS3 Compliant	55100	—	No
LM3485MM/NOPB	Texas Instruments	Active	4.5V ~ 35V	100%	-40°C ~ 125°C	8-VSSOP	RoHS3 Compliant	96400	—	No
LM3485Q1MM/NOPB	Texas Instruments	Active	4.5V ~ 35V	100%	-40°C ~ 125°C	8-VSSOP	RoHS3 Compliant	2140	—	Yes (AEC-Q100)
LM3489MM	Texas Instruments	Last Time Buy	4.5V ~ 35V	100%	-40°C ~ 125°C	8-VSSOP	RoHS3 Compliant	2300	Current Limit, Enable	Yes (AEC-Q100)
LM3489MM/NOPB	Texas Instruments	Active	4.5V ~ 35V	100%	-40°C ~ 125°C	8-VSSOP	RoHS3 Compliant	15700	Current Limit, Enable	Yes (AEC-Q100)
LM3489MMX/NOPB	Texas Instruments	Active	4.5V ~ 35V	100%	-40°C ~ 125°C	8-VSSOP	RoHS3 Compliant	16371	Current Limit, Enable	Yes (AEC-Q100)
LM3489QMM/NOPB	Texas Instruments	Active	4.5V ~ 35V	100%	-40°C ~ 125°C	8-VSSOP	RoHS3 Compliant	10684	Current Limit, Enable	Yes (AEC-Q100)
LM3489QMMX/NOPB	Texas Instruments	Active	4.5V ~ 35V	100%	-40°C ~ 125°C	8-VSSOP	RoHS3 Compliant	3060	Current Limit, Enable	Yes (AEC-Q100)

Engineering Selection Recommendations

For Direct Replacement (Identical Base Part Number):

LM3485MM/NOPB and LM3485MMX/NOPB are direct active equivalents of the obsolete LM3485MMX. Both maintain identical electrical and mechanical specifications with RoHS3 compliance. LM3485MM/NOPB offers the highest inventory availability (96400 pcs) and is the preferred selection for standard applications requiring no additional features.

For Automotive and Enhanced Control Applications:

LM3485Q1MM/NOPB provides automotive-grade qualification (AEC-Q100) while maintaining LM3485 base specifications. This variant is suitable for automotive power management designs requiring industry qualification.

For Parametric Equivalence with Extended Features:

The LM3489 series (LM3489MM/NOPB, LM3489MMX/NOPB, LM3489QMM/NOPB, LM3489QMMX/NOPB) provides full electrical and mechanical equivalence with integrated current limit and enable control features. All LM3489 variants include automotive-grade qualification (AEC-Q100). LM3489MM/NOPB offers the highest inventory (15700 pcs) among the LM3489 series. LM3489MMX/NOPB provides equivalent functionality with 16371 pcs in stock.

Compliance Consideration:

All active substitute parts are RoHS3 compliant, addressing regulatory requirements not met by the obsolete LM3485MMX (RoHS non-compliant).

Frequently Asked Questions (FAQ)

Q: Can LM3485MMX be directly replaced with LM3485MM/NOPB?

A: Yes. LM3485MM/NOPB is a direct active equivalent with identical electrical parameters (4.5V ~ 35V supply, 100% duty cycle, -40°C ~ 125°C operating range), mechanical specifications (8-VSSOP package), and functional characteristics (step-down buck controller, transistor driver output). The primary difference is product status (active vs. obsolete) and RoHS3 compliance.

Q: What is the difference between LM3485 and LM3489 series substitutes?

A: Both series maintain identical voltage supply range, duty cycle, operating temperature, package type, and output configuration. The LM3489 series adds integrated control features (current limit and enable functions) and specifies switching frequency (up to 1MHz). All LM3489 variants include automotive-grade qualification (AEC-Q100), while LM3485 variants do not, except for LM3485Q1MM/NOPB.

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

A: Yes. All substitute parts use 8-TSSOP, 8-MSOP (0.118", 3.00mm width) package with 8-VSSOP supplier device package designation. Pin-to-pin compatibility is maintained across all listed substitutes.

Q: Which substitute part has the best inventory availability?

A: LM3485MM/NOPB has the highest inventory with 96400 pcs in stock. For LM3489 series alternatives, LM3489MMX/NOPB offers 16371 pcs.

Q: Do all substitute parts meet RoHS requirements?

A: All active substitute parts are RoHS3 compliant. The original LM3485MMX is RoHS non-compliant. Compliance with RoHS3 is a key advantage of transitioning to any active substitute part.

Q: Can LM3489 variants be used in designs originally specified for LM3485?

A: Yes, provided the design does not conflict with the additional control features (current limit, enable) present in LM3489 variants. The core electrical and mechanical parameters are equivalent. Designs must accommodate or ignore the additional control pins if present.

Q: What is the significance of the "/NOPB" suffix?

A: The "/NOPB" suffix indicates lead-free (no-lead) packaging and RoHS compliance. Parts with this suffix meet modern environmental and regulatory standards.

Q: Are automotive-qualified variants necessary for non-automotive applications?

A: Automotive-qualified variants (LM3485Q1MM/NOPB, LM3489 series with AEC-Q100) are not required for non-automotive applications. Standard industrial-grade variants (LM3485MM/NOPB) are suitable for general power management applications.

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