Monolithic Power Systems Inc. MPQ4425AGQB-AEC1-Z

Overview

MPQ4425AGQB-AEC1-Z from Monolithic Power Systems is a synchronous step-down LED driver IC designed for automotive front/rear lighting systems. It delivers 1.5A continuous output current, operates from 4V–36V input, integrates 85mΩ/50mΩ MOSFETs, and features AEC-Q100 Grade-1 qualification, 2.2MHz fixed switching frequency, and PWM dimming support down to 100Hz.

For engineers reviewing the MPQ4425AGQB-AEC1-Z datasheet, MPQ4425AGQB-AEC1-Z pinout, MPQ4425AGQB-AEC1-Z application, or MPQ4425AGQB-AEC1-Z equivalent, key selection criteria include its fault-indicating /FAULT pin, forced CCM operation across load range, 0.2V reference voltage for precise current regulation, and CISPR25 Class 5 EMI compliance for automotive deployment.

Technical Context

The MPQ4425AGQB-AEC1-Z uses peak-current-mode control with internal 0.2V reference and valley-current detection for over-current protection. Its fixed 2.2MHz (±200kHz) oscillator enables compact filter design, and frequency foldback to 1.1MHz activates above ~21V input or during short-circuit events.

It integrates high-side and low-side MOSFETs (R_DS(ON) = 85mΩ/50mΩ), employs internal soft-start (0.9ms), and provides open-drain /FAULT reporting for LED open/short and thermal shutdown. The bootstrap circuit supports high-duty-cycle operation with recommended 20Ω BST resistor and 0.1µF BST capacitor.

Key Specifications

Pinout & Package

MPQ4425AGQB-AEC1-Z is housed in a space-saving QFN-13 (2.5mm × 3mm) package with wettable flank option (AEC1 suffix denotes standard non-wettable flank; -AEC1-Z confirms tape-and-reel packaging). Thermal performance is optimized with θ_JA = 60°C/W on 4-layer PCB.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MPQ4425AGQB-AEC1-Z, the wettable flank variant improves manufacturability without changing performance, while the LM3409Q requires additional components and offers no automotive qualification or integrated diagnostics-making MPQ4425AGQB-AEC1-Z optimal for safety-critical, space-constrained automotive lighting.

Availability

MPQ4425AGQB-AEC1-Z is available at Aetrix Electronics and suitable for automotive daytime running lights, front fog lamps, rear combination lamps, and commercial vehicle stop/tail lights requiring stable component supply, AEC-Q100 compliance, and long-term lifecycle support.

Supply support for MPQ4425AGQB-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 control solutions.

The MPQ4425A product line targets automotive lighting applications demanding high efficiency, small form factor, and AEC-Q100 qualification-designed specifically to replace discrete buck controllers in headlamp, DRL, and fog lamp modules.

FAQ

What is the maximum allowable input voltage for MPQ4425AGQB-AEC1-Z?

The absolute maximum input voltage is +40V, but the recommended operating range is 4V to 36V. Operation above 36V risks violating the 36V specification limit during load-dump events; the device includes internal UVLO (3.5V rising threshold) and thermal shutdown (170°C) to prevent damage under overvoltage or overload conditions.

Can MPQ4425AGQB-AEC1-Z drive more than two series LEDs?

Yes, provided the total forward voltage remains within the available headroom: V_IN(min) − V_LED(total) ≥ 1.5V (minimum dropout for regulation). At 4V input, it supports up to 1–2 white LEDs (3.0–3.6V each); at 12V input, up to 3–4 LEDs are feasible. Output current remains regulated at 1.5A as long as thermal limits and minimum on-time (46ns) are respected.

How does the /FAULT pin behave during thermal shutdown?

During thermal shutdown, the /FAULT pin is actively pulled low (≤0.4V at 4mA sink) and remains low until die temperature drops below ~140°C (30°C hysteresis). This open-drain signal can directly interface with a microcontroller GPIO or optocoupler for system-level fault logging without additional conditioning circuitry.

Is an external bootstrap diode required for normal operation?

No-MPQ4425AGQB-AEC1-Z includes an internal bootstrap regulator and does not require an external diode. However, adding an external Schottky diode (e.g., IN4148) between VCC and BST is recommended when duty cycle exceeds 65%, improving high-VIN efficiency by ~2–3% and reducing BST capacitor stress.

What is the purpose of the NC pin (Pin 3)?

Pin 3 is a no-connect terminal with no internal bond wire or circuit connection. It must remain unconnected on the PCB-routing traces to or placing solder paste on this pad may cause assembly defects or unintended parasitic coupling. Its presence accommodates package mold alignment and thermal pad symmetry.

Does MPQ4425AGQB-AEC1-Z support analog dimming?

No-it supports only PWM dimming via the EN/DIM pin (100Hz–2kHz), where LED current scales linearly with duty cycle. Analog dimming (current adjustment via FB voltage) is not supported; the 0.2V reference is fixed and not user-adjustable. For analog control, external current-sense amplifiers or DAC-based solutions would be required.

What is the minimum recommended input capacitor RMS current rating?

The input capacitor must handle ≥0.75A RMS current-calculated as half the maximum LED current (1.5A ÷ 2) per design guidelines. A 10µF X5R/X7R ceramic capacitor rated for ≥1A RMS (e.g., 1210 case, 25V) plus a parallel 0.1µF 0603 capacitor placed adjacent to IN/PGND satisfies both bulk and high-frequency noise requirements.