Monolithic Power Systems Inc. MP4425AGQB-P

Overview

MP4425AGQB-P from Monolithic Power Systems is a synchronous step-down white LED driver IC with integrated 85mΩ/50mΩ MOSFETs, delivering up to 1.5A output current across 4V–36V input range, operating at 2.2MHz fixed frequency, and featuring PWM dimming support (100Hz–2kHz) for automotive front lighting and interior ambient systems.

For engineers reviewing the MP4425AGQB-P datasheet, MP4425AGQB-P pinout, MP4425AGQB-P application, or MP4425AGQB-P equivalent, key selection criteria include its forced CCM mode for stable low-load regulation, 0.2V reference voltage enabling precise current-setting via R_FB, fault indication (/FAULT open-drain), valley-current OCP, and CISPR25 Class 5 EMI compliance for automotive deployment.

Technical Context

The MP4425AGQB-P employs peak-current-mode control with internal 2.2MHz oscillator and fixed-frequency operation, entering frequency foldback (1.1MHz) above ~21V input or during short-circuit conditions. Its error amplifier compares FB voltage to a trimmed 0.2V reference and drives COMP to regulate inductor peak current.

It integrates a bootstrap regulator with 2.2V UVLO and 150mV hysteresis for high-side gate drive, supports forced continuous conduction mode across full load range, and uses valley-current detection for over-current protection-ensuring robust response to LED open/short faults and thermal events up to 170°C shutdown threshold.

Key Specifications

Pinout & Package

MP4425AGQB-P is housed in a thermally enhanced QFN-13 package (2.5mm × 3mm, 0.5mm pitch) with exposed thermal pad (PGND-connected) for PCB-level heat dissipation. The package supports reflow soldering per JEDEC J-STD-020 and achieves θ_JA = 60°C/W on 4-layer board.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous step-down LED driver applications.

Compared with MP4425AGQB-P, the MPQ4425AGQB-P adds automotive qualification without altering functionality, while the LM3409QMY/NOPB trades integration for configurability-making the MP4425AGQB-P optimal for cost-sensitive, space-constrained 1.5A automotive LED modules needing plug-and-play reliability.

Availability

MP4425AGQB-P is available at Aetrix Electronics and suitable for automotive LED headlamps, commercial vehicle interior lighting, and off-road equipment lighting requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MP4425AGQB-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 power management ICs, with over two decades of innovation in DC/DC converters, LED drivers, and motor drivers.

The MP4425A product line targets automotive and industrial LED lighting applications demanding high efficiency, small footprint, and robust fault handling-designed specifically to replace discrete buck solutions with fully integrated, EMI-optimized drivers.

FAQ

What is the maximum allowable input voltage for MP4425AGQB-P?

The absolute maximum input voltage is +40V, but the recommended operating range is 4V to 36V. Exceeding 36V risks triggering frequency foldback and may reduce long-term reliability under sustained overvoltage conditions. Operation above 36V is not guaranteed per datasheet specifications and voids parametric assurance.

Can MP4425AGQB-P drive more than two series LEDs?

Yes-it supports up to four series white LEDs (typical V_F ≈ 3.2V each) at 1.5A, provided the total forward voltage remains ≤ (V_IN − V_SW(drop)). At 12V input, max supported V_OUT is ~10.5V; at 24V input, it extends to ~22V. Inductor saturation current and thermal limits must be verified per application.

Is an external bootstrap diode required for reliable operation?

No-an external bootstrap diode is optional and only recommended for duty cycles above 65% to improve efficiency. The internal bootstrap regulator functions reliably with a 0.1µF capacitor and 20Ω series resistor; IN4148 is the validated diode if added, powered from VCC or VOUT.

How does the /FAULT pin indicate specific fault types?

The /FAULT pin pulls low for all three conditions-LED open, LED short, and thermal shutdown-but does not distinguish between them electrically. Fault type identification requires correlating /FAULT assertion with system context (e.g., measured LED voltage, temperature sensor data, or timing of event relative to startup).

What is the minimum PWM dimming frequency supported?

The minimum supported PWM dimming frequency is 100Hz, as specified in the datasheet's EN/DIM section. Frequencies below 100Hz may cause visible flicker or inconsistent current regulation due to interaction with the 2.2MHz internal clock and soft-start behavior during each PWM on-cycle.

Does MP4425AGQB-P require external compensation components?

No-compensation is fully internal. The error amplifier uses an optimized internal network that eliminates the need for external RC components on the FB pin, simplifying layout and reducing BOM count while maintaining stability across recommended output capacitor ranges (ceramic, tantalum, or electrolytic).

What PCB layout practices are critical for thermal performance?

Essential practices include: (1) connecting the exposed thermal pad directly to a large internal PGND plane using ≥6 thermal vias, (2) routing IN and PGND traces as wide copper pours, (3) placing the 0.1µF VCC capacitor within 2mm of pins 7 and 8, and (4) separating SW/BST traces from FB and AGND to prevent noise coupling-verified on 4-layer boards per MPS layout guidelines.