LM3404MR LED Driver IC Equivalent & Substitute Parts

Part Overview

The LM3404MR is a LED Driver IC from Texas Instruments designed for step-down (buck) topology DC-DC regulation with PWM dimming capability. This single-output regulator delivers 1A output current and operates across a 6V to 42V supply range, making it suitable for automotive-grade lighting applications. The part is currently discontinued at DiGi Electronics, necessitating identification of functionally equivalent alternatives that maintain electrical and mechanical compatibility for new designs and production continuity.

Key Parameters

Parameter	Value
Manufacturer	Texas Instruments
Part Number	LM3404MR
Product Category	Power Management (PMIC) - LED Driver IC
Type	DC DC Regulator
Topology	Step-Down (Buck)
Number of Outputs	1
Voltage Supply Range	6V to 42V
Output Voltage	40V
Output Current	1A
Switching Frequency	1MHz
Dimming Method	PWM
Package Type	8-PowerSOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
Operating Temperature	-40°C to 125°C (TJ)
Grade	Automotive
RoHS Status	RoHS non-compliant
Product Status	Discontinued

Substitute Part Grouping Explanation

Substitution eligibility for the LM3404MR is determined by the following critical parameters:

Primary Matching Criteria:

Topology: Step-Down (Buck) configuration
Number of Outputs: Single output
Output Current Capability: Minimum 1A
Supply Voltage Range: Minimum 6V lower bound, minimum 42V upper bound
Dimming Method: PWM support
Package Compatibility: 8-pin surface mount packages (8-SO, 8-SOIC, or equivalent pin-compatible variants)
Operating Temperature: -40°C minimum, 125°C minimum upper range
Automotive Grade certification

Secondary Compatibility Factors:

Switching Frequency: 1MHz nominal (±20% tolerance acceptable)
Internal Switch: Required
Moisture Sensitivity Level: MSL 3 or better
RoHS Compliance: ROHS3 preferred for new designs

Substitutes are grouped into two categories: direct pin-compatible replacements and functional equivalents with different package footprints. Direct replacements maintain identical pinout and package dimensions. Functional equivalents provide equivalent electrical performance but may require PCB layout modifications due to different package types.

Parameter Comparison

Parameter	LM3404MR	LM3404MR/NOPB	ILD6070XUMA1	IS31LT3350-V1STLS2-TR	LT3491ESC8#TRMPBF	MAX16832AASA+	MIC3202YME	MP2481DH-LF-Z	MP2483DQ-LF-P	MP24893DQ-LF-Z	MP24895GQ-Z
Manufacturer	TI	TI	Infineon	Lumissil	ADI	ADI/Maxim	Microchip	MPS	MPS	MPS	MPS
Topology	Buck	Buck	Buck	Buck	Boost	Buck	Buck	Buck	Buck/Boost	Buck	Buck
Supply Voltage Min (V)	6	6	4.5	6	2.5	6.5	6	4.5	4.5	6	6
Supply Voltage Max (V)	42	42	60	40	12	65	37	36	55	36	36
Output Current (A)	1	1	0.7	0.65	0.35	0.7	1	1.2	2.5	1	0.7
Switching Frequency (MHz)	1	1	1	1	2.3	2	1	1.4	0.5	—	—
Dimming	PWM	PWM	Analog, PWM	Analog, PWM	PWM	PWM	PWM	Analog, PWM	Analog, PWM	Analog, PWM	Analog, PWM
Operating Temp (°C)	-40 to 125	-40 to 125	-40 to 150	-40 to 85	-40 to 85	-40 to 125	-40 to 125	-40 to 125	-40 to 85	-40 to 125	-40 to 125
Package	8-PowerSOIC	8-PowerSOIC	8-SOIC	SOT-23-5	8-VFSOP	8-SOIC-EP	8-SOIC-EP	8-MSOP-EP	10-QFN	6-QFN	6-QFN
Automotive Grade	Yes	Yes	No	No	No	No	No	Yes	Yes	Yes	Yes
RoHS Status	Non-compliant	ROHS3	ROHS3	ROHS3	ROHS3	ROHS3	ROHS3	ROHS3	ROHS3	ROHS3	ROHS3
Product Status	Discontinued	Active	Obsolete	Active	Active	Active	Active	Active	Active	Not For New Designs	Active

Engineering Selection Recommendations

Tier 1 - Direct Replacement (Pin-Compatible, Identical Package):

LM3404MR/NOPB is the primary direct substitute. This part maintains identical electrical specifications, package footprint (8-PowerSOIC), and pinout as the original LM3404MR. The key distinction is product status: LM3404MR/NOPB is active and ROHS3 compliant, whereas the original is discontinued and RoHS non-compliant. This substitution requires no PCB modifications and provides full functional equivalence. Inventory availability is 2140 units.

Tier 2 - Functional Equivalents (Buck Topology, 1A Output, Compatible Supply Range):

MIC3202YME (Microchip Technology) provides 1A output current in an 8-SOIC-EP package with 6V to 37V supply range, 1MHz switching frequency, and PWM dimming. Operating temperature range is -40°C to 125°C. ROHS3 compliant and active product status. Supply voltage upper limit (37V) is below the original 42V specification; verify application requirements before selection.

MP2481DH-LF-Z (Monolithic Power Systems) delivers 1.2A output current in an 8-MSOP-EP package with 4.5V to 36V supply range and 1.4MHz switching frequency. Automotive grade, ROHS3 compliant, active status. Supply voltage upper limit (36V) is below original specification. Supports both analog and PWM dimming.

Tier 3 - Functional Equivalents (Buck Topology, Reduced Output Current):

MAX16832AASA+ (Analog Devices/Maxim) provides 700mA output current in an 8-SOIC-EP package with 6.5V to 65V supply range and 2MHz switching frequency. Operating temperature -40°C to 125°C, ROHS3 compliant, active status. Output current is 30% below original specification; suitable only for applications with reduced current requirements.

ILD6070XUMA1 (Infineon Technologies) provides 700mA output current in an 8-SOIC package with 4.5V to 60V supply range and 1MHz switching frequency. Operating temperature -40°C to 150°C, ROHS3 compliant. Product status is obsolete; not recommended for new designs despite extended temperature range.

Tier 4 - Alternative Topologies (Not Direct Substitutes):

LT3491ESC8#TRMPBF (Analog Devices) uses step-up (boost) topology with 350mA output current, 2.5V to 12V supply range, and 2.3MHz switching frequency. This topology is fundamentally different from the original buck converter and is suitable only for applications requiring voltage step-up rather than step-down regulation. Not recommended as a substitute for buck-based designs.

MP2483DQ-LF-P (Monolithic Power Systems) supports both buck and boost topologies with 2.5A output current in a 10-QFN package. Supply range 4.5V to 55V, 500kHz switching frequency. Automotive grade, ROHS3 compliant, active status. Dual-topology capability and higher current rating exceed original specifications; suitable for designs requiring increased flexibility and current capacity.

Tier 5 - Reduced Pin Count Alternatives (6-Pin QFN Packages):

MP24893DQ-LF-Z and MP24895GQ-Z both use 6-QFN packages with reduced pin counts. MP24893DQ-LF-Z provides 1A output current with 6V to 36V supply range; product status is "Not For New Designs." MP24895GQ-Z provides 700mA output current with 6V to 36V supply range and is active. Both are automotive grade and ROHS3 compliant. These alternatives require PCB redesign due to different package footprint and pin configuration.

Tier 6 - Compact Package Alternative (SOT-23-5):

IS31LT3350-V1STLS2-TR (Lumissil Microsystems) provides 650mA output current in a compact SOT-23-5 package with 6V to 40V supply range and 1MHz switching frequency. ROHS3 compliant, active status. Operating temperature upper limit is 85°C (below original 125°C specification). Smallest footprint option; suitable for space-constrained applications with reduced current requirements.

Frequently Asked Questions (FAQ)

Q: Can I use MP24895GQ-Z as a direct replacement for LM3404MR?

A: MP24895GQ-Z is not a direct pin-for-pin replacement. While it maintains buck topology, 1MHz switching frequency, and automotive-grade certification, it differs in three critical aspects: (1) output current is 700mA versus the original 1A, (2) package is 6-QFN versus 8-PowerSOIC, requiring PCB layout changes, and (3) supply voltage upper limit is 36V versus 42V. Use only if your application current requirement is ≤700mA and supply voltage does not exceed 36V.

Q: Why is LM3404MR/NOPB the recommended substitute?

A: LM3404MR/NOPB is the primary recommendation because it maintains 100% electrical and mechanical compatibility with the original LM3404MR. Identical specifications include 1A output current, 6V to 42V supply range, 1MHz switching frequency, 8-PowerSOIC package, and -40°C to 125°C operating temperature. The only differences are product status (active versus discontinued) and RoHS compliance (ROHS3 versus non-compliant). No PCB modifications are required.

Q: What is the difference between PWM-only dimming and analog/PWM dimming?

A: PWM-only dimming controls LED brightness exclusively through pulse-width modulation of the switching signal. Analog/PWM dimming provides both PWM control and analog voltage control options, offering greater flexibility in dimming implementation. The original LM3404MR supports PWM dimming only. Substitutes with analog/PWM capability are backward-compatible; PWM dimming can be used exclusively if analog control is not required.

Q: Can I use IS31LT3350-V1STLS2-TR in an automotive application?

A: IS31LT3350-V1STLS2-TR is not automotive-grade. While it is ROHS3 compliant and active, it lacks automotive qualification. The original LM3404MR is automotive-grade. If your application requires automotive-grade certification, select from: LM3404MR/NOPB, MP2481DH-LF-Z, MP2483DQ-LF-P, MP24893DQ-LF-Z, or MP24895GQ-Z.

Q: What is the impact of different package types on PCB design?

A: The original LM3404MR uses an 8-PowerSOIC package (0.154" width, 3.90mm). Direct substitutes maintaining this package (LM3404MR/NOPB, ILD6070XUMA1, MAX16832AASA+, MIC3202YME) require no PCB modifications. Alternatives with different packages require layout changes: 8-MSOP (MP2481DH-LF-Z) has different pin spacing; 10-QFN and 6-QFN packages (MP2483DQ-LF-P, MP24893DQ-LF-Z, MP24895GQ-Z) have different footprints and thermal pad configurations; SOT-23-5 (IS31LT3350-V1STLS2-TR) is significantly smaller. Verify PCB layout compatibility before selection.

Q: Why do some substitutes have lower supply voltage upper limits?

A: The original LM3404MR supports 42V maximum supply voltage. Several substitutes (MIC3202YME at 37V, MP2481DH-LF-Z at 36V, MP24893DQ-LF-Z at 36V, MP24895GQ-Z at 36V) have lower upper limits due to different IC design and internal switch ratings. If your application requires operation above 36V, select from: LM3404MR/NOPB (42V), ILD6070XUMA1 (60V), MAX16832AASA+ (65V), or MP2483DQ-LF-P (55V).

Q: Is LT3491ESC8#TRMPBF suitable as a substitute?

A: LT3491ESC8#TRMPBF is not suitable as a substitute for buck-based applications. This part uses step-up (boost) topology, which increases voltage rather than decreasing it. Boost converters are fundamentally different from buck converters in circuit operation and control. Use LT3491ESC8#TRMPBF only if your application specifically requires voltage step-up regulation, not as a replacement for the LM3404MR buck converter.

Q: What does "Not For New Designs" product status mean?

A: "Not For New Designs" indicates the manufacturer no longer recommends this part for new product development, though it may still be available for existing production. MP24893DQ-LF-Z carries this status. For new designs, select from parts with "Active" status: LM3404MR/NOPB, IS31LT3350-V1STLS2-TR, LT3491ESC8#TRMPBF, MAX16832AASA+, MIC3202YME, MP2481DH-LF-Z, MP2483DQ-LF-P, or MP24895GQ-Z.

Q: How do I verify supply voltage compatibility for my application?

A: Identify your application's minimum and maximum supply voltage. The substitute part must support a range that fully encompasses your application voltage. For example, if your application operates from 12V to 40V, the substitute must have minimum ≤12V and maximum ≥40V. The original LM3404MR supports 6V to 42V. LM3404MR/NOPB matches this exactly. MIC3202YME (6V to 37V) would not be suitable for applications requiring 40V to 42V operation.

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