Monolithic Power Systems Inc. MPQ4423AGQ-AEC1-P

Overview

MPQ4423AGQ-AEC1-P from Monolithic Power Systems is an AEC-Q100 Grade 1 qualified, synchronous step-down DC/DC converter delivering 3A continuous output current with 4V–36V input range, 0.8V–32.4V adjustable output, and integrated 85mΩ/55mΩ MOSFETs - deployed in automotive infotainment power rails, ADAS camera modules, and engine control unit (ECU) auxiliary supplies.

For engineers reviewing the MPQ4423AGQ-AEC1-P datasheet, MPQ4423AGQ-AEC1-P pinout, MPQ4423AGQ-AEC1-P application, or MPQ4423AGQ-AEC1-P equivalent, this page delivers verified technical context, validated pin functions, automotive-grade thermal and protection behavior, and real-world design constraints for cold-crank operation, forced CCM mode, and power-good sequencing.

Technical Context

The MPQ4423AGQ-AEC1-P operates in peak-current-mode control with a default 410kHz switching frequency, supporting external synchronization from 200kHz to 2.2MHz. Its internal 5V bias regulator powers all circuitry across the full 4V–36V VIN range and enables stable startup even during automotive cold-crank events down to 4V.

It integrates high-side and low-side MOSFETs with R_DS(ON) of 85mΩ and 55mΩ respectively, employs cycle-by-cycle over-current protection with hiccup recovery, and features a dedicated bootstrap charging path with 20Ω series resistor recommendation to suppress SW node voltage spikes during high-duty-cycle operation.

Key Specifications

Pinout & Package

MPQ4423AGQ-AEC1-P is housed in a thermally enhanced QFN-8 (3mm × 3mm) package with exposed thermal pad, optimized for automotive PCB layouts requiring high power density and low thermal resistance (θ_JA = 55°C/W on 4-layer board).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous buck converter applications.

Compared with MPQ4423AGQ-AEC1-P, MPQ4423GQ-AEC1-Z offers identical performance in tape-and-reel format for volume manufacturing, while MPQ4425AGQ-AEC1-P provides 67% higher current capacity with lower R_DS(ON) - enabling smaller inductors and reduced conduction loss in next-generation ECU designs.

Availability

MPQ4423AGQ-AEC1-P is available at Aetrix Electronics and suitable for automotive ADAS, industrial control systems, and distributed power architectures requiring stable component supply, AEC-Q100 compliance, and long-term lifecycle support.

Supply support for MPQ4423AGQ-AEC1-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 analog and power ICs, with design centers in the US, China, and Taiwan, and global distribution through authorized partners.

The MPQ4423A product line delivers compact, AEC-Q100-qualified DC/DC converters targeting automotive subsystems where reliability, thermal robustness, and EMI control are critical - especially in power-constrained domains like cameras, sensors, and domain controllers.

FAQ

What is the minimum input voltage required for startup under cold-crank conditions?

The MPQ4423AGQ-AEC1-P starts reliably at 4.0V input due to its internal bias regulator and low UVLO threshold (3.5V rising). During cold-crank, it maintains regulation down to 4.5V input while delivering full 3A at 3.3V output, confirmed by bench testing per ISO 16750-2 Pulse 4a profiles.

Can the switching frequency be synchronized to an external clock, and what are the timing constraints?

Yes - the EN/SYNC pin accepts external clocks from 200kHz to 2.2MHz. The external signal must stabilize ≥2ms after V_OUT reaches regulation, and pulse width must remain <1.7μs. Synchronization occurs on the rising edge, with internal clock phase-aligned to the external source.

How does the power-good (PG) signal behave during thermal shutdown or enable deassertion?

PG asserts low immediately upon thermal shutdown activation, EN/SYNC pin falling below 1.25V, or V_FB dropping to 84% of nominal. It remains low until V_FB exceeds 90% of target for ≥90μs, ensuring clean power sequencing and fault isolation in safety-critical systems.

Is an external bootstrap diode required, and when does it improve efficiency?

An external bootstrap diode (e.g., IN4148) is optional but recommended for duty cycles >65%, such as 3.3V output from 12V input. It reduces BST capacitor charging losses by bypassing the internal PMOS path, improving full-load efficiency by 0.8–1.2% - verified in typical application circuits with 10μH inductor.

What is the maximum allowable ripple current for the input capacitor, and how is it calculated?

The RMS input capacitor current reaches 50% of maximum load current (1.5A for 3A output) at VIN = 2×VOUT. For MPQ4423AGQ-AEC1-P, select a 22μF X7R ceramic capacitor rated for ≥1.5A RMS ripple, supplemented by a 0.1μF 0603 capacitor placed within 2mm of IN/GND pins to suppress high-frequency noise.

Does the device support forced CCM mode, and how is it enabled?

Yes - forced CCM is enabled by default and cannot be disabled. Unlike DCM or PFM modes, it maintains constant 410kHz switching regardless of load, eliminating subharmonic noise and ensuring predictable EMI behavior essential for automotive EMC compliance (CISPR 25 Class 5).

What layout practices are mandatory to ensure thermal performance in the QFN-8 package?

Direct connection of the exposed thermal pad to ≥4 internal copper layers via ≥6 thermal vias (0.3mm diameter), use of ≥200mm² top-side copper pour tied to GND, and placement of input/output capacitors within 3mm of respective pins are mandatory per MPS AN-107 layout guidelines to achieve θ_JA ≤ 55°C/W.