Monolithic Power Systems Inc. MPQ4425AGQBE-AEC1-Z

Overview

MPQ4425AGQBE-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 2.2MHz fixed frequency, and qualified to AEC-Q100 Grade-1 for automotive lighting systems.

For engineers reviewing the MPQ4425AGQBE-AEC1-Z datasheet, MPQ4425AGQBE-AEC1-Z pinout, MPQ4425AGQBE-AEC1-Z application, or MPQ4425AGQBE-AEC1-Z equivalent, key selection criteria include its wettable flank QFN-13 package, PWM dimming support (100Hz–2kHz), fault-indicating open-drain /FAULT pin, and forced CCM operation for stable low-ripple current regulation in headlight and DRL modules.

Technical Context

The MPQ4425AGQBE-AEC1-Z employs peak-current-mode control with internal 0.2V reference and valley-current detection for over-current protection. Its fixed 2.2MHz switching frequency enables compact passive filtering, while frequency foldback to 1.1MHz activates above ~21V input or during short-circuit conditions.

It integrates a bootstrap regulator with 2.2V UVLO and 150mV hysteresis for high-side gate drive, supports external BST diode enhancement, and features internal soft-start (0.9ms) with VSS-controlled reference override during startup to prevent output overshoot.

Key Specifications

Pinout & Package

MPQ4425AGQBE-AEC1-Z is housed in a space-saving, AEC-Q100-compliant wettable flank QFN-13 package (2.5mm × 3mm, 0.5mm pitch), enabling automated optical inspection (AOI) of solder joints and enhanced reliability in automotive under-hood environments.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MPQ4425AGQBE-AEC1-Z, the MPQ4425AGQB-AEC1-Z sacrifices solder joint inspectability for identical performance, while the LM3409QMYX/NOPB trades integration and footprint for design flexibility and extended voltage/current headroom - making the MPQ4425AGQBE-AEC1-Z optimal for compact, AOI-validated automotive exterior lighting.

Availability

MPQ4425AGQBE-AEC1-Z is available at Aetrix Electronics and suitable for automotive daytime running lights, headlight modules, and commercial vehicle position lamps requiring stable component supply with full AEC-Q100 traceability and wettable flank process assurance.

Supply support for MPQ4425AGQBE-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 design centers in the US, China, and Taiwan, and global distribution through authorized partners.

The MPQ4425A product line delivers highly integrated, AEC-Q100-qualified LED drivers for automotive exterior lighting, emphasizing compact size, high efficiency, and robust fault protection in harsh operating environments.

FAQ

What is the purpose of the BST pin and how should it be configured?

The BST pin supplies the floating gate drive voltage for the internal high-side MOSFET. It must be connected to the SW node via a 0.1µF ceramic capacitor; a 20Ω resistor in series is strongly recommended to suppress SW node voltage spikes. No external bootstrap diode is required for standard operation, though one (e.g., IN4148) may improve efficiency at duty cycles >65%.

How does PWM dimming work on the EN/DIM pin, and what are the timing constraints?

PWM dimming is implemented by applying a 100Hz–2kHz square wave to the EN/DIM pin; LED current scales linearly with duty cycle. If applied before startup, the PWM on-time must exceed 2ms to allow soft-start completion; after startup, no minimum on-time applies. The pin has internal 400kΩ pull-down and 6.5V Zener clamping for robustness.

What failure conditions trigger the /FAULT pin, and how is it electrically interfaced?

The open-drain /FAULT pin is pulled low during LED open-circuit, LED short-circuit, or thermal shutdown (>170°C). It requires an external pull-up resistor (e.g., 100kΩ to VCC) to operate. Leakage current is <100nA when inactive, and sink capability is 4mA at 0.4V - compatible with standard microcontroller GPIO interrupt inputs.

Can the MPQ4425AGQBE-AEC1-Z operate below 4V input, and what happens during undervoltage lockout?

No - the device disables below 3.2V (UVLO rising threshold) and remains off until input rises above 3.8V. Hysteresis is 400mV, so turn-on occurs at ~3.5V and turn-off at ~3.1V. During UVLO, all internal regulators and switching cease, quiescent current drops to 12µA, and /FAULT remains high (no fault asserted).

What is the maximum achievable LED string voltage, and how is it limited?

The maximum LED string voltage is constrained by the 36V absolute maximum input rating minus the minimum required headroom for regulation. With typical 0.2V feedback reference and internal MOSFET drops, practical string voltage is up to ~34V (e.g., 10× 3.4V white LEDs). Exceeding this risks violating the 40V absolute max on SW pin during transients, requiring careful layout and input transient suppression.

Is thermal derating required for continuous 1.5A operation in a 70°C ambient environment?

Yes - with θ_JA = 60°C/W, power dissipation at 1.5A/12V_IN is ~0.45W, resulting in ~27°C rise above ambient. At 70°C ambient, junction temperature reaches ~97°C - within the -40°C to +125°C operating range. However, at 36V_IN, losses increase significantly; full 1.5A output requires heatsinking or airflow above 50°C ambient per thermal simulation.

Does the MPQ4425AGQBE-AEC1-Z support constant-voltage regulation, or is it current-only?

It is strictly a constant-current LED driver - the FB pin regulates current via a single sense resistor using the 0.2V internal reference. There is no built-in voltage regulation mode or CV feedback path. Output voltage is determined solely by the LED forward voltage and string configuration; the IC maintains set current regardless of V_LED changes within its 4V–36V input window.