Monolithic Power Systems Inc. MPQ4425BGQBE-AEC1-Z

Overview

MPQ4425BGQBE-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 MPQ4425BGQBE-AEC1-Z datasheet, MPQ4425BGQBE-AEC1-Z pinout, MPQ4425BGQBE-AEC1-Z application, or MPQ4425BGQBE-AEC1-Z equivalent, this device supports PWM dimming (100Hz–2kHz), features fault indication (/FAULT), internal soft start, and CISPR25 Class 5 EMI compliance - critical for automotive LED headlamp and DRL designs requiring robust thermal and over-current protection.

Technical Context

The MPQ4425BGQBE-AEC1-Z employs peak-current-mode control with fixed 400kHz oscillator and forced continuous conduction mode (CCM), enabling stable regulation from no-load to full 1.5A output. Its valley-current-detection OCP responds within 10μs during LED short/open faults, while internal 0.2V reference and error amplifier drive COMP voltage to modulate high-side MOSFET on-time.

Bootstrap charging relies on SW-to-BST capacitor topology with internal 2.2V UVLO on the floating driver; thermal shutdown activates at 170°C with 30°C hysteresis, and /FAULT provides open-drain fault signaling for LED short, open, or thermal events - all implemented in a single QFN-13 (2.5mm×3.0mm) package with wettable flanks for automated optical inspection.

Key Specifications

Pinout & Package

MPQ4425BGQBE-AEC1-Z is housed in a wettable-flank QFN-13 package (2.5mm × 3.0mm, 0.5mm pitch), optimized for automated optical inspection and thermal performance (θ_JC = 2.5°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MPQ4425BGQBE-AEC1-Z, MPQ4425BGQB-AEC1 sacrifices AOI capability for lower unit cost, while LM3409QMYX/NOPB trades integration for design flexibility - making the wettable-flank AEC-Q100 variant optimal for volume automotive LED lighting where solder-joint reliability and fault diagnostics are mandatory.

Availability

MPQ4425BGQBE-AEC1-Z is available at Aetrix Electronics and suitable for automotive headlights, daytime running lights, and commercial vehicle lighting requiring stable component supply, AEC-Q100 compliance, and CISPR25 Class 5 EMI certification.

Supply support for MPQ4425BGQBE-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 over 20 years of expertise in DC/DC conversion, LED drivers, and motor drivers.

The MPQ4425B product line delivers AEC-Q100-qualified synchronous buck LED drivers targeting automotive exterior lighting, emphasizing integration, thermal robustness, and EMI compliance for space-constrained headlamp modules.

FAQ

What is the purpose of the /FAULT pin, and how should it be interfaced?

The /FAULT pin is an open-drain output that pulls low during LED short circuit, open circuit, or thermal shutdown. It must be externally pulled up to V_CC (typically with a 100kΩ resistor) to generate a logic-high signal during normal operation. This pin enables direct connection to microcontroller GPIOs or dashboard warning systems for real-time fault reporting without additional level-shifting circuitry.

Can MPQ4425BGQBE-AEC1-Z operate below 4V input?

No - the device incorporates an under-voltage lockout (UVLO) with a rising threshold of 3.5V (±0.3V). Input voltage below 3.2V disables operation, and hysteresis ensures clean turn-on at ~3.6V. This prevents unstable startup during automotive cold-crank events where battery voltage may dip transiently below 4V but recovers above 3.6V.

How does the BST pin function, and what capacitor value is required?

BST supplies gate drive voltage to the high-side MOSFET via a bootstrap capacitor connected between BST and SW pins. A 0.1μF X7R ceramic capacitor is required; placement must minimize loop inductance. A 20Ω resistor between SW and BST is strongly recommended to damp ringing and reduce voltage spikes during switching transitions.

Is PWM dimming supported, and what are the timing constraints?

Yes - apply a 100Hz–2kHz PWM signal directly to the EN/DIM pin. Minimum amplitude is 1.8V; dimming duty cycle linearly controls average LED current. If applied before soft start completes, the on-time must exceed 2ms to ensure proper startup; no such restriction applies after soft start finishes.

What thermal derating applies at elevated ambient temperatures?

With θ_JA = 42°C/W on MPS's EVQ4425B-QB-00A evaluation board, maximum continuous power dissipation drops from 2.08W at 25°C to ~1.1W at 85°C ambient. At T_A = 105°C, output current must be reduced to ≤1.0A to maintain T_J ≤125°C - verified via thermal imaging on production-grade PCB layouts.

Does the device support analog dimming via the FB pin?

No - the FB pin is strictly for current-sense feedback referencing the internal 0.2V reference. Analog dimming is not supported; brightness control is exclusively via PWM on EN/DIM or external current-source modulation. Attempting voltage injection into FB disrupts regulation and may trigger OCP or fault conditions.

What is the minimum inductor value recommended for stable operation?

For 400kHz operation and 1.5A output, MPS recommends ≥6.8μH with ≥2.5A saturation current. Lower values increase peak inductor current and ripple, risking OCP triggering or reduced efficiency. The datasheet's typical application uses 10μH; 6.8μH is the validated minimum for full-load stability across temperature and input range.