LM2751SD-A LED Driver IC Equivalent & Substitute Parts

Part Overview

The LM2751SD-A is a LED Driver IC manufactured by Texas Instruments, designed as a 1-output DC DC regulator with switched capacitor (charge pump) topology for PWM dimming applications. This component delivers 80mA output current and operates across a 2.8V to 5.5V supply range, making it suitable for backlight applications.

The LM2751SD-A is classified as obsolete. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain reliability, and support ongoing production or maintenance of systems utilizing this component.

Substiute Parts

LM2751SD-A

Texas InstrumentsIn Stock: 2459LM2751SD-A Datasheet

Current PartRFQ

AP5726FDCG-7

Diodes IncorporatedIn Stock: 19759AP5726FDCG-7 Datasheet

MFR RecommendedRFQ

LT3956IUHE#TRPBF

Analog Devices Inc.In Stock: 1150LT3956IUHE#TRPBF Datasheet

MFR RecommendedRFQ

MCP1643-I/MS

Microchip TechnologyIn Stock: 3196MCP1643-I/MS Datasheet

MFR RecommendedRFQ

MIC2282YMM

Microchip TechnologyIn Stock: 10043MIC2282YMM Datasheet

MFR RecommendedRFQ

RT9361AGE

Richtek USA Inc.In Stock: 55307RT9361AGE Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the LM2751SD-A are identified based on the following critical parameters that determine functional compatibility:

Primary Substitution Criteria:

• Single output DC DC regulator topology
• PWM dimming capability
• Supply voltage range compatibility (minimum 2.8V to 5.5V overlap)
• Output voltage of 5V or adjustable to 5V
• Current output capacity of 80mA or greater
• Backlight application suitability
• Operating temperature range of -40°C to 85°C or wider
• Surface mount packaging

Substitution Groups:

Group 1: Switched Capacitor (Charge Pump) Topology — Direct topology match with PWM dimming and 5V output. Includes RT9361AGE, which maintains the same charge pump architecture and 5V output specification.

Group 2: Step-Up (Boost) Topology with PWM Dimming — Alternative topology providing higher current capacity and supply voltage flexibility. Includes AP5726FDCG-7, MCP1643-I/MS, and MIC2282YMM, all supporting PWM dimming and backlight applications with enhanced current handling.

Group 3: Multi-Topology Flexible Regulators — Advanced regulators supporting multiple topologies (Flyback, SEPIC, Buck, Boost) with both analog and PWM dimming. Includes LT3956IUHE#TRPBF, offering extended voltage and current capabilities for complex LED driver applications.

Parameter Comparison

Engineering Selection Recommendations

RT9361AGE — Recommended as the primary direct substitute. This part maintains identical topology (switched capacitor charge pump), matching 5V output voltage, and equivalent current capacity (110mA vs. 80mA). Operating temperature range (-40°C to 85°C) aligns with the original specification. The part is RoHS3 compliant and carries active product status, ensuring long-term availability. Package transition from 10-WFDFN to SOT-23-6 requires PCB layout modification but represents the closest functional equivalent.

AP5726FDCG-7 — Suitable for applications requiring higher current capacity (750mA switch current). This boost topology regulator supports the same supply voltage range (2.7V to 5.5V) and PWM dimming for backlight applications. RoHS3 compliance and active status provide supply chain continuity. Package change to 6-UDFN requires design revision.

MCP1643-I/MS — Applicable for designs tolerating boost topology conversion. Offers 550mA current capacity with 5V output and PWM dimming. Extended supply voltage range (0.5V to 5V) provides flexibility for low-voltage input scenarios. RoHS3 compliant with active product status. 8-MSOP package represents a significant footprint reduction.

MIC2282YMM — Provides highest current capacity (1.1A switch current) with extended supply voltage range (0.9V to 15V) and 35V output capability. Suitable for applications requiring voltage step-up beyond 5V. Lacks specified PWM dimming in datasheet parameters. RoHS3 compliant and active status confirmed.

LT3956IUHE#TRPBF — Advanced multi-topology regulator supporting Flyback, SEPIC, Buck, and Boost configurations with both analog and PWM dimming. Highest current capacity (3.3A) and extended operating temperature range (-40°C to 125°C). Requires minimum 4.5V supply voltage. RoHS3 compliant with active status. 36-QFN package represents significant complexity increase; suitable only for applications requiring multi-topology flexibility.

Frequently Asked Questions (FAQ)

Q: Can RT9361AGE directly replace LM2751SD-A without circuit modification?

A: RT9361AGE maintains functional equivalence in topology, output voltage, and dimming capability. However, package transition from 10-WFDFN to SOT-23-6 requires PCB layout redesign. Electrical schematic compatibility depends on identical pin configuration and control signal requirements, which must be verified against respective datasheets.

Q: What is the primary difference between charge pump and boost topology substitutes?

A: The LM2751SD-A uses switched capacitor (charge pump) topology, which is inherently limited to fixed voltage conversion ratios and lower current capacity. Boost (step-up) topology substitutes (AP5726FDCG-7, MCP1643-I/MS, MIC2282YMM) provide adjustable output voltage and higher current handling through inductor-based energy storage. Charge pump topology offers lower EMI and simpler external component requirements.

Q: Is RoHS compliance a critical factor for LM2751SD-A substitution?

A: The original LM2751SD-A is RoHS non-compliant. All recommended substitutes are RoHS3 compliant. If the end application or regional regulations mandate RoHS compliance, substitute selection is restricted to active, compliant alternatives. If legacy RoHS non-compliant status is acceptable, this constraint does not apply.

Q: Which substitute offers the closest current capacity match to the 80mA specification?

A: RT9361AGE provides 110mA output current, representing the closest match to the original 80mA specification. This 30mA margin provides adequate headroom for typical backlight LED driver applications without requiring circuit redesign.

Q: Can boost topology substitutes operate at the same supply voltage range as LM2751SD-A?

A: AP5726FDCG-7 and MCP1643-I/MS both support the 2.7V to 5.5V range, overlapping with the original 2.8V to 5.5V specification. MIC2282YMM extends the minimum supply to 0.9V, providing additional flexibility. LT3956IUHE#TRPBF requires minimum 4.5V supply, restricting compatibility with lower voltage input scenarios.

Q: What packaging considerations apply when selecting a substitute?

A: The LM2751SD-A uses 10-WFDFN (3x3mm) packaging. Substitutes employ different packages: RT9361AGE (SOT-23-6), AP5726FDCG-7 (6-UDFN), MCP1643-I/MS and MIC2282YMM (8-MSOP), and LT3956IUHE#TRPBF (36-QFN). Package selection impacts PCB footprint, thermal management, and board layout complexity. Smaller packages (SOT-23-6, 6-UDFN) reduce board area; larger packages (36-QFN) improve thermal dissipation for high-current applications.

Q: Are all substitute parts currently in active production status?

A: Yes. All recommended substitutes carry active product status, ensuring ongoing manufacturing and supply chain availability. The original LM2751SD-A is obsolete, making active substitutes essential for new designs or production continuity.