RT8476GS LED Driver IC Equivalent & Substitute Parts

Part Overview

The RT8476GS is an LED Driver IC manufactured by Richtek USA Inc., designed for step-down (buck) and step-up (boost) DC-DC regulation with single output. This component is classified as obsolete, which necessitates identification of functionally equivalent alternatives for new designs and ongoing production support. The RT8476GS operates across a 4.5V to 40V supply range and is rated for automotive-grade applications in lighting and signage systems, with operating temperature range of -40°C to 85°C.

Key Parameters

Parameter	RT8476GS Value
Manufacturer	Richtek USA Inc.
Category	Power Management (PMIC)
Type	DC DC Regulator
Topology	Step-Down (Buck), Step-Up (Boost)
Number of Outputs	1
Voltage - Supply (Min)	4.5V
Voltage - Supply (Max)	40V
Internal Switch(s)	No
Applications	Lighting, Signage
Operating Temperature	-40°C ~ 85°C (TA)
Grade	Automotive
Package / Case	8-SOIC (0.154", 3.90mm Width)
RoHS Status	ROHS3 Compliant
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution of the RT8476GS is determined by the following critical parameters:

Topology Compatibility: The RT8476GS supports both step-down (buck) and step-up (boost) configurations. Substitute parts must support at least one of these topologies to maintain functional equivalence.
Supply Voltage Range: The 4.5V to 40V input range is a primary constraint. Substitute parts must accommodate this range or a compatible subset.
Single Output Configuration: All substitutes must provide single output regulation.
Package Form Factor: The 8-SOIC package constrains mechanical compatibility; however, alternative packages may be acceptable depending on PCB redesign feasibility.
Automotive Grade Compliance: The RT8476GS carries automotive-grade qualification; substitutes with automotive qualification are preferred for direct replacement.
RoHS3 Compliance: All identified substitutes maintain ROHS3 compliance, meeting regulatory requirements.

Substitute parts are grouped into two categories based on topology alignment:

Category A - Buck/Boost Dual Topology: Parts supporting both step-down and step-up operation, directly matching the RT8476GS topology.

Category B - Single Topology (Buck or Boost): Parts supporting either buck or boost operation, suitable for applications utilizing only one topology.

Parameter Comparison

Parameter	RT8476GS	MP2483DS-LF-Z	LT3518HUF#TRPBF	LM3406MH/NOPB	LM3530TME-40/NOPB	LT1937ES5#TRMPBF	AL8861Y-13	PAM2803AAF095
Manufacturer	Richtek USA Inc.	Monolithic Power Systems Inc.	Analog Devices Inc.	Texas Instruments	Texas Instruments	Analog Devices Inc.	Diodes Incorporated	Diodes Incorporated
Topology	Buck, Boost	Buck, Boost	Buck, Boost	Buck	Boost	Boost	Buck	Boost
Voltage - Supply (Min)	4.5V	4.5V	3V	6V	2.7V	2.5V	4.5V	0.9V
Voltage - Supply (Max)	40V	55V	30V	42V	5.5V	10V	40V	5.5V
Number of Outputs	1	1	1	1	1	1	1	1
Internal Switch(s)	No	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Operating Temperature	-40°C ~ 85°C (TA)	-40°C ~ 85°C (TA)	-40°C ~ 150°C (TJ)	-40°C ~ 125°C (TJ)	-40°C ~ 85°C (TA)	-40°C ~ 85°C (TA)	-40°C ~ 85°C (TA)	-40°C ~ 85°C (TA)
Grade	Automotive	Automotive	-	Automotive	-	-	-	-
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Product Status	Obsolete	Active	Active	Active	Active	Active	Active	Active

Engineering Selection Recommendations

Primary Substitute - MP2483DS-LF-Z (Monolithic Power Systems Inc.)

The MP2483DS-LF-Z provides the closest functional match to the RT8476GS. Both devices support buck and boost topologies, operate across overlapping supply voltage ranges (4.5V to 55V for MP2483DS-LF-Z), and carry automotive-grade qualification. The MP2483DS-LF-Z is in active production status, ensuring long-term availability. Package form factor differs (14-SOIC versus 8-SOIC), requiring PCB layout modification. RoHS3 compliance is maintained.

Secondary Substitute - LT3518HUF#TRPBF (Analog Devices Inc.)

The LT3518HUF#TRPBF supports both buck and boost topologies with supply range of 3V to 30V, encompassing the RT8476GS operating window. This device is in active production and carries ROHS3 compliance. Operating temperature range extends to 150°C (junction), providing thermal margin beyond the RT8476GS specification. Package form factor is 16-QFN (4x4), requiring significant PCB redesign.

Topology-Specific Alternatives

For applications utilizing only buck topology, the LM3406MH/NOPB (Texas Instruments) provides automotive-grade qualification with active production status and PWM dimming capability across 6V to 42V supply range.

For applications utilizing only boost topology, the LM3530TME-40/NOPB (Texas Instruments) operates across 2.7V to 5.5V supply range with active production status and PWM dimming capability. The LT1937ES5#TRMPBF (Analog Devices Inc.) provides boost topology with 2.5V to 10V supply range and active production status.

All recommended substitutes maintain ROHS3 compliance and are in active production, ensuring regulatory compliance and supply chain continuity.

Frequently Asked Questions (FAQ)

Q: Can the MP2483DS-LF-Z directly replace the RT8476GS without PCB modification?

A: The MP2483DS-LF-Z provides functional equivalence in topology and electrical specifications but uses a 14-SOIC package versus the RT8476GS 8-SOIC package. PCB layout modification is required to accommodate the different pin count and package dimensions.

Q: What is the significance of the RT8476GS being classified as obsolete?

A: Obsolete status indicates the manufacturer has discontinued production. Existing inventory may be available through authorized distributors, but long-term supply cannot be guaranteed. Active production substitutes ensure continued availability for new designs and production runs.

Q: Are all substitute parts automotive-grade qualified?

A: No. The MP2483DS-LF-Z and LM3406MH/NOPB carry automotive-grade qualification. The LT3518HUF#TRPBF, LM3530TME-40/NOPB, LT1937ES5#TRMPBF, AL8861Y-13, and PAM2803AAF095 do not carry automotive-grade designation. For automotive applications, MP2483DS-LF-Z or LM3406MH/NOPB are preferred.

Q: What is the difference between internal switch presence in the RT8476GS versus substitute parts?

A: The RT8476GS does not include an internal switch, requiring external switching components. All identified substitute parts include integrated internal switches, reducing external component count and PCB area. This represents a functional improvement in integration level.

Q: Can I use a boost-only topology part if my application requires buck functionality?

A: No. Topology selection must match application requirements. Boost-only parts (LM3530TME-40/NOPB, LT1937ES5#TRMPBF, PAM2803AAF095) cannot provide step-down regulation. Buck-only parts (LM3406MH/NOPB, AL8861Y-13) cannot provide step-up regulation. Dual-topology parts (MP2483DS-LF-Z, LT3518HUF#TRPBF) support both functions.

Q: How do supply voltage ranges affect substitution compatibility?

A: The RT8476GS operates from 4.5V to 40V. Substitute parts must accommodate the specific voltage levels required by the application within this range. MP2483DS-LF-Z (4.5V to 55V) and LT3518HUF#TRPBF (3V to 30V) both cover the RT8476GS range. Parts with narrower ranges (LM3530TME-40/NOPB: 2.7V to 5.5V) are suitable only for low-voltage applications within their specified limits.

Q: What packaging considerations apply when selecting a substitute?

A: The RT8476GS uses 8-SOIC (0.154", 3.90mm width) package. Substitute parts use different packages: MP2483DS-LF-Z (14-SOIC), LT3518HUF#TRPBF (16-QFN), LM3406MH/NOPB (14-HTSSOP), and others. Package selection affects PCB layout, thermal management, and assembly compatibility. Evaluate package availability and manufacturing capability before final selection.

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