Monolithic Power Systems Inc. MP2481DH-LF-P

Overview

MP2481DH-LF-P from Monolithic Power Systems is a 36V, 1.2A white LED driver IC supporting both buck and inverting buck-boost topologies, featuring fixed 1.4MHz switching frequency, integrated 0.30Ω MOSFET, 0.2V feedback reference, and combined EN/DIM control for analog and PWM dimming - used in automotive interior lighting and LCD backlight panels.

For engineers reviewing the MP2481DH-LF-P datasheet, MP2481DH-LF-P pinout, MP2481DH-LF-P application, or MP2481DH-LF-P equivalent, key selection criteria include input voltage range (4.5–36V), peak current capability (1.2A), OVP threshold programmability via external resistor divider, thermal shutdown at 150°C, and compatibility with low-ESR ceramic output capacitors.

Technical Context

This current-mode LED driver integrates a 0.30Ω internal N-channel MOSFET switch and operates at a fixed 1.4MHz frequency (with fold-back to 120kHz under overvoltage fault). Its dual-mode topology supports step-down and inverting step-up/down configurations, enabling output voltages above or below input without polarity reversal of LED strings.

The EN/DIM pin provides unified control: analog dimming across 0.7–1.4V (0–100% LED current), PWM dimming with >1.4V amplitude, and hard shutdown below 0.4V. The separate INGND reference pin isolates dimming logic ground from power return (VSS), critical for stable operation in buck-boost mode where VSS is not tied to input ground.

Key Specifications

Pinout & Package

MP2481DH-LF-P is housed in an 8-pin MSOP-EP (MSOP8E) package with exposed thermal pad on the bottom side - not electrically connected to VSS, requiring independent grounding per layout guidelines to maximize thermal performance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar white LED driver applications.

Compared with MPQ2481DG-AEC1-LF-Z, the MP2481DH-LF-P offers identical performance at lower cost for non-automotive use, while LT3466-1EDD demands more external components and lacks integrated OVP - making MP2481DH-LF-P optimal for cost-sensitive, space-constrained LED systems requiring full protection and simplicity.

Availability

MP2481DH-LF-P is available at Aetrix Electronics and suitable for automotive interior lighting, LCD backlight panels, handheld computers, and portable GPS devices requiring stable component supply, RoHS-compliant packaging, and long-term production continuity.

Supply support for MP2481DH-LF-P includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Monolithic Power Systems (MPS) is a fabless semiconductor company specializing in high-performance analog and power ICs, with core expertise in DC/DC conversion, LED drivers, motor drivers, and battery management solutions.

The MP2481 belongs to MPS's white LED driver product line, engineered specifically for high-efficiency, compact, and fault-resilient constant-current LED control in automotive, industrial, and portable display applications.

FAQ

What is the maximum LED string voltage the MP2481DH-LF-P can drive in buck-boost mode?

In inverting buck-boost configuration, the MP2481DH-LF-P regulates LED current regardless of output polarity; its absolute maximum VDD-to-VSS rating is 40V, and OVP protection triggers at 1.23V on the OVP pin - meaning the actual maximum LED string voltage depends on the external resistor divider. For example, with R1=39kΩ and R2=10kΩ, the OVP threshold is set to ~4.8V at the output node, allowing safe operation with up to ~40V total string voltage when VIN is low.

Can the MP2481DH-LF-P operate with only one LED in the string?

Yes - the MP2481DH-LF-P has no minimum LED requirement and functions stably with zero or one LED. Its current-mode architecture and 0.2V feedback reference enable accurate regulation even at very low forward voltages, eliminating the need for dummy loads or minimum-string constraints common in voltage-mode LED drivers.

How does the EN/DIM pin handle simultaneous enable and dimming commands?

The EN/DIM pin combines both functions: voltage below 0.4V disables the IC; 0.7–1.4V provides linear analog dimming (0–100% current); above 1.4V enables full current and accepts PWM signals. Internal circuitry separates the logic - analog control adjusts the error amplifier reference, while PWM toggles the internal RS flip-flop directly, ensuring no conflict between modes.

Why is the INGND pin separate from VSS, and what happens if they are shorted?

INGND provides a dedicated reference for the EN/DIM pin to isolate dimming logic from high-noise power return paths. Shorting INGND to VSS in buck-boost mode creates a ground loop that injects switching noise into the dimming control path, causing erratic current regulation, audible noise, or unintended shutdown - the datasheet explicitly prohibits this connection in non-buck applications.

What is the purpose of the BST capacitor, and what value is recommended?

The BST capacitor (typically 10nF X7R ceramic) forms a bootstrap supply between SW and BST pins to generate gate drive voltage >VDD for the internal MOSFET. It must be placed within 2mm of the IC with short, wide traces; insufficient capacitance causes weak gate drive, increased R_DS(on), and thermal runaway at high duty cycles.

Does the MP2481DH-LF-P support I²C or other digital interfaces for dimming control?

No - the MP2481DH-LF-P supports only analog voltage and PWM signal inputs on the EN/DIM pin. It does not include digital communication interfaces such as I²C, SPI, or SMBus. For digitally addressable dimming, designers must implement external MCU-based PWM generation or select a different LED driver family like MPS's MP4000 series.

How does the MP2481DH-LF-P respond to an open LED string condition?

When an LED string opens, FB voltage drops near 0V, causing the error amplifier to drive maximum duty cycle. If VDD–VSS reaches 38V or OVP pin voltage hits 1.23V, the internal switch latches off. Recovery occurs automatically once input voltage drops and OVP pin voltage falls below 1.13V (1.23V – 0.1V hysteresis), restoring normal regulation without manual reset.