Monolithic Power Systems Inc. MP2481DH-LF

Overview

MP2481DH-LF from Monolithic Power Systems is a 36V, 1.2A, 1.4MHz white LED driver IC supporting both buck and inverting buck-boost topologies. It integrates a 0.30Ω internal MOSFET switch, delivers up to 95% efficiency, and provides analog/PWM dimming via a single EN/DIM pin - used in LCD backlight panels with 3-series/9-parallel WLED strings at 180mA total output.

For engineers reviewing the MP2481DH-LF datasheet, MP2481DH-LF pinout, MP2481DH-LF application, or MP2481DH-LF equivalent, key selection criteria include its 4.5–36V input range, 0.2V feedback reference, cycle-by-cycle current limiting, open-string protection, and MSOP8E package with exposed thermal pad for thermal management in space-constrained LED lighting designs.

Technical Context

The MP2481DH-LF employs current-mode control with fixed 1.4MHz switching frequency and slope compensation for stable operation across wide duty cycles. Its error amplifier regulates LED current by maintaining 0.2V across the external sense resistor, while the integrated 1.2A peak-current-limited MOSFET enables direct drive of high-brightness LED loads without external switches.

It supports dual-mode topology configuration: buck mode for VIN > VLED (e.g., automotive 12V supply driving 3×WLEDs), and inverting buck-boost for VIN < |VLED| (e.g., 5V input powering –12V LED string). Protection features include input overvoltage lockout (3.1–3.7V UVLO), thermal shutdown at 150°C, and OVP-triggered foldback at 120kHz when VOVP < 0.4V.

Key Specifications

Pinout & Package

MP2481DH-LF is housed in an 8-pin MSOP8E package with exposed thermal pad on the underside - not electrically connected to VSS, requiring separate thermal land connection per JEDEC MO-187 AA-T standard.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LT3466-1 and TPS61165, MP2481DH-LF uniquely combines 36V input, integrated 0.30Ω MOSFET, programmable OVP, and dual-mode topology in MSOP8E - offering highest integration and protection density for industrial and automotive LED lighting.

Availability

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

Supply support for MP2481DH-LF 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, headquartered in California and serving global industrial, automotive, and consumer markets since 1997.

The MP2481 belongs to MPS's white LED driver product line, engineered specifically for high-efficiency, thermally robust constant-current LED control in space-constrained and thermally demanding applications such as automotive displays and portable electronics.

FAQ

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

In inverting buck-boost configuration, the MP2481DH-LF supports output magnitudes up to 36V (|V_OUT| ≤ V_IN + V_SW rating), enabling up to 36V negative output with proper inductor and diode selection - verified in Figure 4 (3-series/9-parallel, 180mA) and confirmed by absolute max ratings (V_SW–V_SS = –0.3V to V_IN + 0.3V).

Can the MP2481DH-LF operate without an external bootstrap capacitor?

No - the BST pin requires a 10nF ceramic capacitor connected between BST and SW to generate the gate drive voltage for the internal high-side MOSFET. Omitting this capacitor prevents proper switch turn-on and causes immediate functional failure, as specified in the PIN FUNCTIONS section and Typical Application Circuits (Figures 3–5).

How does the EN/DIM pin distinguish between analog and PWM dimming modes?

Analog dimming occurs when a DC voltage between 0.7V and 1.4V is applied to EN/DIM relative to INGND - linearly scaling LED current from 0% to 100%. PWM dimming requires a square wave ≥1.4V amplitude and 100Hz–1kHz frequency; the IC internally detects edge transitions and modulates current accordingly without external timing components.

Is the exposed thermal pad on the MSOP8E package electrically connected to VSS?

No - the exposed pad is internally connected only to VSS per the PACKAGE REFERENCE diagram, but the datasheet explicitly warns "Do not Connect to Input Ground (INGND) for Boost, Buck-Boost applications" and states it is tied to VSS. Layout best practice is to solder it to a dedicated thermal land tied to VSS with multiple vias, not to INGND or other nets.

What happens during open LED string conditions, and how is recovery handled?

When LED strings open, FB voltage drops near 0V, causing the controller to increase duty cycle until either V_DD–V_SS reaches 38V or OVP pin voltage hits 1.23V - triggering shutdown. Recovery occurs automatically when input voltage or OVP voltage falls below hysteresis thresholds (0.1V for OVP), allowing normal regulation to resume without manual reset.

Does the MP2481DH-LF require external compensation components for loop stability?

No - the error amplifier and current-mode control architecture are internally compensated. Stability is achieved with standard external components: input/output capacitors, sense resistor, OVP divider, and bootstrap capacitor - as validated in all Typical Application Circuits and confirmed by "no external compensation required" in the APPLICATION INFORMATION section.

What is the minimum recommended inductor value for buck-mode operation at 12V input and 3W LED load?

For 12V input driving three 3W white LEDs (~9.6V total V_F, 700mA), the recommended inductance is 4.7µH (per Table 1 and Figure 3), with DC resistance <200mΩ and saturation current ≥900mA. This satisfies the design equation L = (V_IN–V_OUT)×V_OUT/(ΔI_L×f_SW×V_IN) using 30% ripple current (210mA) and 1.4MHz frequency.