Monolithic Power Systems Inc. MPQ4425BGQB-AEC1-Z

Overview

MPQ4425BGQB-AEC1-Z 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 fixed 400kHz switching frequency, and qualified to AEC-Q100 Grade 1 for automotive front/rear lighting systems.

For engineers reviewing the MPQ4425BGQB-AEC1-Z datasheet, MPQ4425BGQB-AEC1-Z pinout, MPQ4425BGQB-AEC1-Z application, or MPQ4425BGQB-AEC1-Z equivalent, this page provides verified technical context, validated QFN-13 pin functions, CISPR25 Class 5 EMI compliance data, fault-indication behavior, and real-world dimming performance under 100Hz–2kHz PWM control.

Technical Context

The MPQ4425BGQB-AEC1-Z implements peak-current-mode control with internal 0.2V reference and error amplifier driving COMP voltage to regulate LED current via valley-current detection OCP. Its forced CCM operation ensures stable 400kHz switching from no-load to full 1.5A load without frequency foldback under normal conditions.

It integrates dual power MOSFETs (HS R_DS(ON) = 85mΩ, LS R_DS(ON) = 50mΩ), bootstrap gate driver with 2.2V UVLO, and open-drain /FAULT pin asserting low on LED short/open or thermal shutdown at 170°C. The 0.1μF VCC decoupling capacitor is mandatory; BST-SW requires external 20Ω resistor + ceramic capacitor for spike suppression.

Key Specifications

Pinout & Package

MPQ4425BGQB-AEC1-Z is housed in a wettable flank QFN-13 package (2.5mm × 3.0mm, 0.5mm pitch), optimized for automated optical inspection (AOI) and thermal performance in automotive PCBs. Exposed thermal pad must be soldered to inner-layer copper pour for θ_JA = 42°C/W on 4-layer EVB.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MPQ4425BGJ-AEC1-Z, the QFN-13 variant offers 58% lower thermal resistance and wettable flanks for AOI, making it preferred for high-power automotive lighting. Versus LM3409QMYX/NOPB, it delivers faster time-to-market with integrated power stage and diagnostic features but less flexibility in frequency or current scaling.

Availability

MPQ4425BGQB-AEC1-Z is available at Aetrix Electronics and suitable for automotive front headlamp DRL, rear combination lamps, interior ambient lighting, and adaptive driving beam sub-modules requiring stable component supply with AEC-Q100 qualification and long-term production support.

Supply support for MPQ4425BGQB-AEC1-Z 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 core expertise in DC/DC conversion, LED drivers, and motor control solutions for automotive, industrial, and consumer markets.

The MPQ4425B product line targets AEC-Q100-compliant LED lighting applications, emphasizing integration, EMI robustness, and thermal resilience in harsh automotive environments - specifically engineered for space-constrained, high-reliability exterior lighting modules.

FAQ

What is the minimum input voltage required for reliable startup?

The MPQ4425BGQB-AEC1-Z has an input UVLO rising threshold of 3.5V typical, with 400mV hysteresis. Reliable startup occurs at ≥3.8V, and the device sustains regulation down to 4V per datasheet specifications. Below 3.5V, the IC remains in shutdown and draws only 12μA quiescent current.

Can the /FAULT pin drive an LED directly without a microcontroller?

Yes - the /FAULT pin is an open-drain N-channel MOSFET rated for 4mA sink current at 0.4V. It can directly drive a standard 2mA LED with a 2.2kΩ pull-up resistor to 5V or 12V, providing visible fault indication without additional logic circuitry.

Is the 400kHz switching frequency adjustable?

No - the oscillator is factory-trimmed to 400kHz with ±25% variation over temperature and process. There is no external frequency programming pin or resistor option; frequency foldback only occurs during fault conditions like short-circuit or soft-start.

What is the maximum allowable BST capacitor value?

The BST capacitor must be a 0.1μF X7R ceramic type placed between BST and SW pins. While no absolute maximum is specified, exceeding 0.22μF risks VCC regulator instability due to interaction with internal bootstrap charging circuitry, as noted in the datasheet's VCC decoupling guidance.

Does the device support analog dimming via the FB pin?

No - the MPQ4425BGQB-AEC1-Z only supports PWM dimming via the EN/DIM pin. Analog dimming by injecting current into FB is not supported; the FB pin is strictly a high-impedance (30–100nA) voltage-sense input referenced to the internal 0.2V bandgap.

How does thermal shutdown interact with /FAULT assertion?

Thermal shutdown triggers immediate /FAULT pin pull-down within 10μs, as confirmed by oscilloscope waveforms in the datasheet's "LED Open Recovery" and "Thermal Shutdown" test figures. The /FAULT signal remains asserted until die temperature falls below 140°C (30°C hysteresis), at which point the IC resumes normal operation.

What is the recommended PCB layout for the PGND connection?

PGND pins (11,12,13) and the exposed thermal pad must be connected using ≥6 thermal vias (0.3mm diameter) to an inner-layer solid copper pour. The PGND trace to the input capacitor should be wide (>1.5mm) and direct, avoiding splits or narrow necks that increase impedance and EMI radiation.