LM3404MRX LED Driver IC Equivalent & Substitute Parts

Part Overview

The LM3404MRX is a LED Driver IC manufactured by Texas Instruments, designed as a 1-output DC-DC regulator with step-down (buck) topology and PWM dimming capability. This part delivers 1A output current across a 6V to 42V supply range and operates at 1MHz frequency. The device is classified as discontinued at DiGi Electronics, making equivalent and substitute parts necessary for ongoing design support and production continuity. The part carries automotive-grade qualification and operates across -40°C to 125°C junction temperature range.

Key Parameters

Parameter	Value
Manufacturer	Texas Instruments
Part Number	LM3404MRX
Category	Power Management (PMIC)
Type	DC DC Regulator
Topology	Step-Down (Buck)
Number of Outputs	1
Voltage Supply (Min)	6V
Voltage Supply (Max)	42V
Voltage Output	40V
Current Output / Channel	1A
Frequency	1MHz
Dimming	PWM
Operating Temperature	-40°C ~ 125°C (TJ)
Grade	Automotive
Package / Case	8-PowerSOIC (0.154", 3.90mm Width)
RoHS Status	RoHS non-compliant
Product Status	Discontinued at DiGi Electronics

Substitute Part Grouping Explanation

Substitution for the LM3404MRX is determined by the following critical parameters:

Primary Substitution Criteria:

Topology: Step-Down (Buck) configuration
Output Configuration: Single output
Dimming Method: PWM capability
Current Rating: Minimum 1A output capability
Supply Voltage Range: Minimum 6V input support
Operating Temperature: -40°C minimum to 125°C maximum
Mounting Type: Surface mount
Automotive Grade: Preferred for consistency

Substitution Categories:

Direct Parametric Equivalent: LM3404MRX/NOPB matches all electrical and mechanical parameters of the original part. This variant differs only in packaging format (Cut Tape & Digi-Reel versus original packaging) and RoHS compliance status (ROHS3 Compliant versus non-compliant). Product status is Active, ensuring continued availability.

Functional Equivalents with Enhanced Specifications: Parts including A6216KLPTR-T, AL8861MP-13, and ILD6150XUMA1 maintain step-down buck topology with PWM dimming but offer increased current ratings (1.5A to 2A) or expanded supply voltage ranges. These parts are suitable where the original 1A specification is insufficient or where higher supply voltage tolerance is required.

Extended Topology Alternatives: LT3477EUF#PBF and LT3593EDC#TRMPBF represent alternative topologies (Flyback, SEPIC, Boost) and are included for applications where the buck topology may not be optimal. These parts require circuit redesign and are not direct drop-in replacements.

Lower Current Alternatives: MAX16822AASA/V+ and LTC3490ES8#PBF serve applications with reduced current requirements (350mA) and are suitable only where the 1A specification can be reduced.

Parameter Comparison

Parameter	LM3404MRX	LM3404MRX/NOPB	A6216KLPTR-T	AL8861MP-13	ILD6150XUMA1	LT3474IFE-1#PBF	MAX16822AASA/V+	MAX20051AUD/V+
Manufacturer	Texas Instruments	Texas Instruments	Allegro MicroSystems	Diodes Incorporated	Infineon Technologies	Analog Devices Inc.	Analog Devices Inc./Maxim	Analog Devices Inc./Maxim
Topology	Step-Down (Buck)	Step-Down (Buck)	Step-Down (Buck)	Step-Down (Buck)	Step-Down (Buck)	Step-Down (Buck)	Step-Down (Buck)	Step-Down (Buck)
Number of Outputs	1	1	1	1	1	1	1	1
Voltage Supply (Min)	6V	6V	4.5V	4.5V	4.5V	4.6V	6.5V	4.5V
Voltage Supply (Max)	42V	42V	55V	40V	60V	36V	65V	65V
Current Output / Channel	1A	1A	2A	1.5A	1.5A	1A	350mA	2A
Frequency	1MHz	1MHz	—	1MHz	1MHz	200kHz ~ 2MHz	2MHz	400kHz
Dimming	PWM	PWM	Analog, PWM	Analog, PWM	Analog, PWM	PWM	PWM	Analog, PWM
Operating Temperature (Min)	-40°C	-40°C	-40°C	-40°C	-40°C	-40°C	-40°C	-40°C
Operating Temperature (Max)	125°C (TJ)	125°C (TJ)	125°C (TA)	85°C (TA)	150°C (TJ)	125°C (TA)	125°C (TA)	125°C
Grade	Automotive	Automotive	Automotive	—	—	Automotive	Automotive	—
Package / Case	8-PowerSOIC	8-PowerSOIC	16-TSSOP-EP	8-TSSOP-EP	8-SOIC-EP	16-TSSOP-EP	8-SOIC	14-TSSOP-EP
RoHS Status	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Product Status	Discontinued	Active	Active	Active	Active	Active	Active	Active

Engineering Selection Recommendations

For Direct Replacement (Recommended First Choice): LM3404MRX/NOPB is the optimal substitute. This part maintains identical electrical specifications, package footprint, and pinout as the original LM3404MRX. The primary advantage is active product status with 25,400 units in stock, ensuring supply continuity. The part achieves ROHS3 compliance, addressing environmental regulatory requirements where the original non-compliant variant may present procurement restrictions.

For Applications Requiring Higher Current Capacity: AL8861MP-13 (1.5A) or A6216KLPTR-T (2A) are suitable where load current exceeds 1A. Both maintain step-down buck topology with PWM dimming. AL8861MP-13 operates to 85°C maximum ambient temperature, which is lower than the original 125°C junction specification. A6216KLPTR-T extends to 55V supply maximum and includes AEC-Q100 automotive qualification. Package changes require PCB layout modification.

For Extended Supply Voltage Range: ILD6150XUMA1 supports 4.5V to 60V input range, exceeding the original 42V maximum. This part maintains 1.5A output current and 1MHz frequency. Operating temperature extends to 150°C junction, providing thermal margin. Package change from 8-PowerSOIC to 8-SOIC-EP requires layout revision.

For Reduced Current Applications: MAX16822AASA/V+ delivers 350mA output current in an 8-SOIC package matching the original form factor. This part is suitable only where application current requirements are 350mA or less. Supply voltage range extends to 65V maximum.

For Automotive-Grade Consistency: A6216KLPTR-T and LT3474IFE-1#PBF both carry automotive-grade designation with AEC-Q100 qualification. These parts are preferred for automotive lighting applications where grade consistency is required across the bill of materials.

Frequently Asked Questions (FAQ)

Q: Can LM3404MRX/NOPB be used as a direct drop-in replacement for LM3404MRX?

A: Yes. LM3404MRX/NOPB is a parametric equivalent with identical electrical specifications, operating temperature range (-40°C to 125°C), current rating (1A), supply voltage range (6V to 42V), and package footprint (8-PowerSOIC). The only differences are packaging format (Cut Tape & Digi-Reel) and RoHS compliance status (ROHS3 Compliant). No circuit modifications are required.

Q: What is the primary reason to substitute the LM3404MRX?

A: The LM3404MRX is discontinued at DiGi Electronics, creating supply chain risk. LM3404MRX/NOPB provides the same functionality with active product status and 25,400 units in stock. For applications where supply voltage or current requirements differ, alternative parts offer expanded specifications.

Q: Can AL8861MP-13 replace LM3404MRX in all applications?

A: AL8861MP-13 is functionally compatible for applications requiring 1.5A or less output current. However, the maximum ambient operating temperature is 85°C (TA), compared to the original 125°C (TJ). This temperature difference may be significant for high-temperature environments. The package changes from 8-PowerSOIC to 8-TSSOP-EP, requiring PCB layout modification. Verify thermal requirements before substitution.

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

A: The original LM3404MRX supports PWM dimming only. Substitute parts offering Analog/PWM dimming (A6216KLPTR-T, AL8861MP-13, ILD6150XUMA1, MAX20051AUD/V+) provide additional dimming flexibility through analog voltage control in addition to PWM. Existing PWM-only designs remain compatible with these parts; the analog capability is optional.

Q: Does package size affect substitution compatibility?

A: Yes. The original LM3404MRX uses 8-PowerSOIC (0.154", 3.90mm width). Substitutes with different packages (16-TSSOP, 8-TSSOP, 14-TSSOP) require PCB layout redesign, including trace routing, via placement, and thermal pad configuration. Pin count and pinout differences must be verified against schematic requirements. LM3404MRX/NOPB maintains the original 8-PowerSOIC package, eliminating layout changes.

Q: Are all substitute parts RoHS3 compliant?

A: All substitute parts listed are ROHS3 compliant. The original LM3404MRX is RoHS non-compliant. If RoHS compliance is required for procurement or regulatory purposes, LM3404MRX/NOPB or any alternative part in this list satisfies compliance requirements.

Q: Which substitute part is best for automotive applications?

A: For automotive-grade consistency, A6216KLPTR-T and LT3474IFE-1#PBF both carry automotive-grade designation with AEC-Q100 qualification. LM3404MRX/NOPB also maintains automotive grade. A6216KLPTR-T offers the highest current capacity (2A) and supply voltage range (55V maximum) among automotive-qualified options.

Q: Can LT3477EUF#PBF or LT3593EDC#TRMPBF be used as replacements?

A: These parts are not direct replacements. LT3477EUF#PBF supports multiple topologies (Flyback, SEPIC, Buck, Boost) and operates at lower supply voltages (2.5V to 25V), incompatible with the original 6V to 42V range. LT3593EDC#TRMPBF is a step-up (boost) topology with 45mA output current, fundamentally different from the original step-down buck design. Both require complete circuit redesign and are suitable only for new applications with different topology requirements.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message